Electronic Four-Wheel Steering Diagnosis and Service
Contents
1. The 4WS control unit stores a fault code and illuminates the 4WS indicator light if a defect occurs in the system even if the defect is temporary Always ask the customer about the conditions that caused the 4WS indicator light to come on and duplicate this condition during a road test If the AWS light is not illuminated during the road test the system is satisfactory electronically and does not require further electronic diagnosis The troubleshooting procedures in the vehicle manufac turer s service manual assume that the problem is present at the time of diagnosis Trouble Code Display with Ignition Switch On CAUTION When diagnosing a computer system never connect or ground any terminals unless instructed to do so in the vehicle manufacturer s service manual This action may damage electronic components CAUTION When diagnosing a computer system never disconnect or connect any computer system component with the ignition switch on unless instructed to do so in the vehicle manufacturer s service manual This action may damage the computer or system components CAUTION When performing electronic diagnosis on a vehicle equipped with an air bag most vehicle manufacturers recommend turning the ignition switch off dis connecting the negative battery cable and waiting one minute before proceeding with elec tronic component diagnosis or service CAUTION When performing electronic diagnosis on a vehicle equipped with an air bag fol2. Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 419 F Rear sub steering angle sensor S Locknut O ring N TrA Locking tabs Actuator housing Figure 13 19 Tightening and staking the inner tie rod Figure 13 20 Removing the rear sub steering angle boot clamps sensor 2 Remove the two mounting bolts in the rear main steering angle sensor and then remove the sensor from the actuator housing Figure 13 21 Note the position of the dowel pins and discard the O ring a SERVICE TIP Cover the rear main steering sensor and rear sub steering SNS computer in sensor openings in the actuator housing with masking tape or its equivalent to relation us ball screw keep dirt and foreign material out of the actuator housing rotation in the rear steering actuator The rear main steering 3 Install the locknut and a new O ring on the rear sub steering angle sensor Rear main 9 steering angle sensor Figure 13 21 Removing the rear main steering angle sensor 419 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 420 p Place a light coating of grease on the O ring and install the sensor in the actuator housing Rotate the sensor until it touches the tapered shaft and back it out one half turn Tighten the locknut finger tight Final adjustment of the rear sub steering angle sensor is completed with the actuator installed in the vehicle Place a light coating of grease on the rear main steering angle sensor O ring and install th
3. Ends CAUTION Never apply axial impact or rotational force to the shaft screw in the rear steering actuator Either of these actions may cause internal actuator damage Inner tie rod boots must be replaced if they are cracked split deteriorated or damaged Follow these steps for tie rod and tie rod end installation 1 Install the tie rod ends so the marks on the tie rod ends nuts and tie rods are aligned and tighten the tie rod nuts to the specified torque 2 Screw each inner tie rod onto the shaft screw while holding the lock washer so its tabs are in the inner tie rod end The stop washer must be installed on the shaft screw with the chamfered side facing outward Figure 13 15 3 Drive the special holding tool between the actuator housing and the stop washer with a soft hammer Figure 13 16 4 Hold the shaft screw with the holding tool and tighten the inner tie rod end to the specified torque 5 Bend the lock washer tabs against the flat on the inner tie rod end 6 Remove the special holding tool and apply silicone grease to the sliding surface of the tie rod Figure 13 17 Place a light coating of silicone grease inside the tie rod boot 7 Apply the vehicle manufacturer s recommended grease to the circumference of the inner tie rod joint housing 8 Install the boots on the actuator housing then install the boot bands with the locking tabs properly positioned in relation to the actuator housing Figure 13 18 4
4. and Steering Task Inspect diagnose ad just service or replace components of electronically controlled steering systems Tools and Materials Tie rod end puller Torque wrench Describe the Vehicle Being Worked On Year Make Model VIN Engine type and size Procedure Task Completed 1 Raise the vehicle on a hoist or lift the rear of the vehicle with a floor jack and support h the chassis with safety stands placed under the chassis at the vehicle manufacturer s recommended locations 2 Remove the cotter pin and nut from each tie rod end h 3 Install a 12 millimeter mm nut on each tie rod end until the nuts are flush with the h tie rod stud 4 Install the special tool on the tie rod end and with the tool arms parallel tighten the h screw on the tool to loosen the tie rod end Repeat the procedure on both tie rod ends 5 Remove the nuts from the tie rods and remove the tie rods from the steering arms h 6 Remove the rear steering actuator cover h 7 Remove the the cap bolt and washer and install the rear steering center lock pin Is the rear steering center lock pin installed Yes No Instructor check 8 Remove the ground cable connector and all wiring harness connectors on the rear steering actuator Are the ground cable connector and all wiring hamess connectors removed Yes No Instructor check 435 Knowles SM Ch_13 qxd Task Completed h 9
5. is cancelled when the ignition switch is turned off However the 4WS indicator light is illuminated again when the ignition switch is turned on and the 4WS control unit detects the problem again Trouble Codes Representing Temporary Driving Conditions Codes 70 71 73 and 74 represent problems resulting from abnormal or harsh driving conditions Figure 13 3 When the 4WS control unit detects one of these problems it does not illuminate the 4WS indicator light but these codes are flashed during the diagnostic procedure Rear Steering Actuator Service Rear Steering Actuator Removal CAUTION Many steering service and diagnostic procedures require the installa tion of the rear steering center lock pin in the rear steering actuator to lock this unit in the centered position If this lock pin is not installed diagnosis will be inaccurate CAUTION Do not start the engine with the rear steering center lock pin in place This action may damage the lock pin and rear steering actuator gt Start lt Main al lt Sub gt Start lt Main gt Code Code Code Code Code 12 22 22 12 22 E a 8 4 4 8 8 4 4 3 Light ON Light OFF ILS 2 1 6 1 6 3 Valve 8 4 4 8 8 4 check Figure 13 2 Trouble codes in main and sub processors obtained with engine running 412 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 413 p OPERATION 4WS INDICATOR LIGHT T
6. 14 02 3 30 PM Page 436 F Instructor s Response 11 12 13 14 15 Remove the four mounting bolts and bracket and remove the rear steering actuator 10 Install the rear steering actuator the four mounting bolts the and bracket The arrow on the bracket must face upward Is the arrow on the bracket facing upward Yes No Instructor check Tighten the rear steering actuator mounting bolts to the specified torque Specified rear steering actuator mounting bolt torque Actual rear steering actuator mounting bolt torque CAUTION Tighten the castelated nut on the tie rod ends to the specified torque then tighten these nuts enough to align the slots in the nut with the hole in the tie rod pin Do not loosen the nut to align the nut slots with the tie rod pin hole If this nut is loosened to align the slots with the hole the nut may become loose in service Reconnect the tie rod ends to the steering arms and tighten the castelated nut to the specified torque If necessary tighten the nut slightly to align the nut slots with the tie rod pin hole Specified tie rod end castelated nut torque Actual tie rod end castelated nut torque Install the cotter pin in the nut and tie rod end pin openings and bend one leg of the cotter pin downward over the nut Bend the other cotter pin leg upward over the top of the tie rod end pin Are the cotter pins properly in
7. 17 ae Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 418 p Shaft screw SS Q Slot EE y Tab Ny Inner j Q tie rod Stopper washer chamfered side Lock facing outward washer holder Figure 13 15 Installing the inner tie rod end on the Figure 13 16 Installing the special tool to hold the shaft shaft screw screw while tightening the inner tie rod end Locking tabs Left Boot boot band Silicone grease coat the sliding surface Locki of the rack end ene tabs Tube clamp Figure 13 17 Lubrication of the inner tie rod joint Figure 13 18 Proper boot band position in relation to housing the actuator housing CAUTION While staking the boot clamps be careful not to damage the inner tie rod boots 9 Tighten the boot bands and bend both sets of locking tabs over the band Figure 13 19 Tap lightly on the doubled over portion of the band to reduce its height and stake a ae the locking tabs firmly The rear sub steering angle sensor sends a i voltage signal to the Remove and Replace Rear Steering Actuator Sensors 4WS computer in relation to the amount _ Follow these steps to remove and replace the rear sub steering angle sensor and the rear main Gf rack movement in steering angle sensor the rear steering 1 Loosen the rear sub steering angle sensor locknut and rotate the sensor to thread it actuator out of the housing Figure 13 20 Discard the sensor O ring 418 ae
8. Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 409 Electronic Four Wheel Steering Diagnosis and Service Upon completion and review of this chapter you should be able to L Perform a preliminary inspection on a four wheel steering 4WS system L Perform a trouble code diagnosis on a 4WS system with the ignition switch on L Perform a trouble code diagnosis on a 4WS system with the engine running L Remove and replace the rear steering actua tor L Remove and replace the tie rod ends on L Remove and replace the rear main steering angle sensor L Remove and replace the rear sub steering angle sensor I Perform an electronic neutral check on a AWS system I Adjust the front main steering angle sensor L Adjust the front sub steering angle sensor L Adjust the rear sub steering angle sensor the rear steering actuator L Remove and replace tie rods and boots on the rear steering actuator Service and adjustments on 4WS systems with adjustable sensors must be performed precisely as explained in the vehicle manufacturer s service manual Inaccurate sensor adjustments may cause improper rear wheel steering operation and this may result in reduced steering control Always follow the service and adjustment procedures carefully and accurately Preliminary Inspection Prior to any four wheel steering diagnosis the following concerns should be considered Have any suspension modifications been made th
9. VIN Engine type and size Procedure Task Completed 1 Road test the vehicle and describe the steering problems that indicate the rear steering actuator tie rods and tie rod ends require replacement 2 Visually inspect the rear steering actuator tie rods and tie rod ends and list the parts that require replacement Explain the reasons for your diagnosis 3 Mark the relative position of the tie rod end locknut and tie rod with a wax marker h Are the tie rod tie rod end and locknut properly marked Yes No 4 Hold the tie rod end with a wrench and loosen the locknut 437 Knowles SM Ch_13 qxd Task Completed h h h 9 14 02 3 30 PM Page 438 p 5 Remove the tie rod end 6 Remove the boot bands and clamps from the inner tie rod ends 7 Place the flat side of the rack holding tool toward the actuator housing and drive the 11 12 13 14 15 special rack holding tool between the actuator housing and the stop washer with a soft hammer Is the rack holding tool properly installed with flat side toward the actuator housing Yes No Straighten the tabs on the tie rod lock washer Are the tabs straightened on tie rod lock washer Yes No W4 SERVICE TIP Hold the special holding tool firmly while loosening the tie rod A to avoid applying rotational force to the shaft screw in the actuator Hold the shaft screw w
10. WS control unit actually contains two processing units that are referred to as the main and sub processing units Each processing unit can store a maximum of ten trouble codes If the trou ble code diagnosis is performed with the engine running the code display indicates whether the codes are stored in the main or sub processor ISIS CS Jumper Service check wire connector Figure 13 1 Dual terminal service check connector positioned behind the center console 411 a Knowles SM Ch_13 qxd 9 14 02 Classroom Manual Chapter 13 page 304 3 30 PM Page 412 F When the service connector terminals are connected with a jumper wire and the engine is started the 4WS indicator light follows this sequence if there are trouble codes in the main and sub processors 1 blinks quickly once when the ignition switch is tumed on 2 pauses for 3 seconds 3 displays codes stored in the main processor 4 pauses for 1 6 seconds 5 blinks quickly for 3 seconds to indicate a separation between the main and sub processor codes D pauses for 1 6 seconds 7 displays codes stored in the sub processor 8 pauses for 3 seconds and then repeats the cycle Figure 13 2 Main Steering Angle Sensor Trouble Code If a defect occurs in the main steering angle sensor system the clock radio 10 A fuse must be dis connected to cancel the 4WS indicator light When defects occur in other parts of the electronic AWS system the 4WS indicator light
11. and B D Neither A norB The Honda Prelude 4WS system uses a main and a sub processing unit each storing 10 trouble codes If the 4WS light on the dash blinks quickly and repeatedly for three seconds it means A a DTC is stored in the main processor B a DTC is stored in the sub processor C the system is moving from the main to the sub processor memory D a DTC sequence will be repeated Honda Prelude temporary abnormal or harsh driving 4WS DTCs range fom to A 07 14 B 70 74 10 C if the steering wheel is turned with the engine running and a rear wheel against a curb the 4WS indicator light is illuminated D driving the car with the parking brake on has no effect on the 4WS indicator light While servicing and adjusting electronically controlled four wheel steering systems A the 4WS indicator light will indicate DTCs and the electronic neutral check at the same time B the parking brake must be released during the front steering sensor test mode C the ignition switch must be on during the front steering test mode D the brake pedal must be depressed during the rear steering test mode The Honda Prelude 4WS light has gone on and remains on Technician A says that before performing any diagnostic tests the 10A fuse for the clock radio should be removed Technician B says to retrieve the DTC the 4WS control unit connector must be disconnected Who is correct A A only B B
12. at would affect steering Are the tire sizes the same as specified by the vehicle manufacturer Are the tires inflated to the pressure specified by the vehicle manufacturer Is the power steering belt adjusted to the vehicle manufacturer s specified tension Oe ee IS Is the power steering pump reservoir filled to the proper level with the type of fluid specified by the vehicle manufacturer 6 Is the engine idling at the speed specified by the vehicle manufacturer Is the idle speed steady 7 Is the steering wheel original equipment Fail Safe Function If the four wheel steering 4WS control unit senses a failure in the system the control unit switches to a fail safe mode In this mode the control unit stores a trouble code or codes and illuminates the 4WS indicator light to inform the driver that a problem exists in the system When this mode is entered the 4WS control unit shuts off voltage to the rear steering unit and the rear wheels remain in the straight ahead position 409 CHAPTER Basic Tools Basic technician s tool set Service manual Jumper wire Floor jack Safety stands Wax marker Silicone grease Chassis lubricant Cotter pins Length of stiff wire A fail safe mode may be called a backup mode The Society of Automotive Engineers SAE J1930 terminology is an attempt to standardize electronics terminology in the automotive industry In the SAE J1930 terminology the term malfunction
13. bands properly installed Yes No Are the locking tabs properly staked Yes No Instructor check Instructor s Response 439 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 440 F
14. been in a rear end collision recently and when the body work was completed the 4WS indicator light problem started occurring The technician informed the customer that a 4WS system diagnosis and inspection should be performed Since the 4WS indicator light was not illuminated the technician concluded that a trouble code diagnosis would probably not provide any diagnostic answers However the technician checked the system for codes in case there was a code caused by abnormal or harsh driving which would not cause the indicator light to be illuminated When the technician raised the vehicle on a hoist it was clearly visible that many of the rear suspension and body parts had been replaced recently Even the rear steering actuator cover had been replaced The technician removed the rear steering actuator cover to inspect the wiring on the actuator All the wiring connectors were inspected including the terminals on the rear main steering angle sensor When the technician inspected the rear sub steering angle sensor wiring hamess he found this hamess had been punctured by a sharp object near the sensor The technician probed the sensor wires at the sensor and connected a pair of ohmmeter leads from each wire at the sensor to the corresponding colored wire in the sensor connector Each wire showed a normal zero ohm resistance The technician repeated these ohmmeter connections and wiggled the wires at the damaged location On one of the wires the oh
15. cally neutral position 11 Slowly turn the rear sub steering angle sensor counterclockwise until the 4WS indica tor light goes off and mark the sensor in relation to the housing 12 Slowly rotate this sensor clockwise until the 4WS indicator light starts to blink and mark the sensor in relation to the housing Turn the sensor to the center position between where the indicator light went off and the light started to blink Figure 13 36 Hold the sensor in this position and tighten the locknut to the specified torque 13 Turn off the ignition switch 14 Ifthe rear sub steering angle sensor wiring is twisted disconnect the connector straighten the harness and reconnect the connector 15 Disconnect the jumper wire from the service check connector 16 Remove the rear steering center lock pin and install the cap bolt and washer Tighten the cap bolt to the specified torque Classroom Manual 17 Install the rear steering actuator cover and perform the electronic neutral check Chapter 13 page 307 described earlier in this chapter Photo Sequence 13 shows a typical procedure for diagnosing an electronically controlled four wheel steering system 428 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 429 p Photo Sequence 13 Typical Procedure for Diagnosing an Electronically Controlled Four Wheel Steering System P13 1 Road test the vehicle to check P13 2 Raise the vehicle on a lift and P13 3 Lower the vehicle and locate the AWS o
16. d Boot Removal and Replacement Tie rod end boots must be replaced if they are cracked split deteriorated or loose Follow these steps to remove and replace the tie rod end boots CAUTION Do not put grease on the boot installation shoulder and tapered section of the ball pin in the tie rod end Grease may cause these components to become loose CAUTION Do not allow dust dirt or foreign material to enter the tie rod end ball joint or boot because this contamination causes rapid component wear 1 Use a large screwdriver to pry the old boot from the tie rod end 2 Pack the interior of the new boot with the vehicle manufacturer s recommended grease and place a light coating of grease on the boot lip 3 Wipe the grease off the sliding surfaces of the ball pin with a shop towel then pack the lower area around the ball pin and body with grease Figure 13 13 Boot Grease Tie rod end Figure 13 13 Packing the boot and tie rod end with grease 416 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 417 F Special driving tool Tie rod end Figure 13 14 Driving the boot onto the tie rod end with a special driving tool 4 Use the special driving tool to install the new boot on the tie rod end Figure 13 14 5 Wipe any grease from the tapered section of the ball pin with a shop towel Apply Tie rod boot driving sealant around the lower edge of the boot and tie rod body tool Installation of Tie Rods and Tie Rod
17. eel puller Figure 13 31 Removing the steering wheel 425 The front main steering angle sensor sends a voltage signal to the AWS computer in relation to steering wheel rotation Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 426 F Front main steering MON angle sensor Yellow paint mark Figure 13 32 Yellow paint mark on the front main steering angle sensor indicating the elec tronically neutral sensor position 4 Check to see if the yellow paint mark on the front main steering angle sensor is fac ing straight down Figure 13 32 When this paint mark is facing down the front main steering angle sensor is in the electronically neutral position 5 Ifthe yellow paint mark on the front main steering angle sensor is not facing down ward temporarily install the steering wheel with the spokes in the horizontal posi tion Turn the steering wheel until this yellow paint mark is facing downward 6 Return the steering wheel to the horizontal position and remove the steering wheel 7 Install the steering wheel aligning it with the serration that makes the spoke angle closest to horizontal Be sure the steering wheel openings fit over the pins on the The cable reel contains cable reel for the air bag system Figure 13 33 Do not push down hard on the a conductive ribbon steering wheel until the serrations and cable reel pins are properly aligned When the that connects the air serrations and cable reel pins are pr
18. end of the wire positioned over the steering wheel marks Be sure the front wheels are straight ahead with the tip of the wire over the center mark on the steering wheel Fig ure 13 27 Be sure the wire is securely taped to the top of the instrument panel 4 Connect a jumper wire to the 4WS service check connector terminals This is the same connection for obtaining 4WS control unit trouble codes Check and verify the trouble codes prior to the electronic neutral check The 4WS indicator light will not indicate the electronic neutral check and trouble codes at the same time 5 Pull the parking brake fully on until the parking brake warning light is on and turn on the ignition switch to set the front steering sensor test mode Front Sensor Inspection Electronic Neutral Check Follow these steps to check the front main steering sensor 1 With the ignition switch on tum the steering wheel slowly to the left and slowly to the right until the 4WS indicator light comes on Repeat this step several times to find 422 ae Knowles SM Ch_13 qgxd 9 14 02 3 30 PM Page 423 p a Figure 13 27 Front wheels straight ahead and wire pointer positioned over the center mark on the steering wheel the exact steering wheel position where the 4WS indicator light is illuminated for more than two seconds 2 The 4WS indicator light should be illuminated when the steering wheel is 9 mm 0 4 in to the left and right of the center mark on the s
19. ension with a floor jack and place safety stands under the proper chassis locations specified by the car manufacturer All four wheels must be off the floor Connect a jumper wire across the terminals in the 4WS system service check connec tor and be sure any trouble codes have been displayed 427 ae Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 428 p Center Center I Light starts to blink Light off Turning ea direction Turning Light starts to blink direction l l Figure 13 35 Adjusting the front sub steering angle Figure 13 36 Adjusting the rear sub steering angle sensor sensor 3 Release the parking brake and tum the ignition switch on Be sure the parking brake waming light goes off 4 Turn off the ignition switch 5 Remove the cap bolt and washer and install the rear steering center lock pin 6 Remove the rear sub steering angle sensor wire from the clamp and disconnect the wiring harness connector 7 Loosen the rear sub steering angle sensor locknut Tighten this locknut fully by hand then back it off approximately one half turn 8 Connect the rear sub steering angle sensor connector and set the front wheels in the straight ahead driving position 9 Turn on the ignition switch 10 Push the left rear wheel fully to the left by hand and then push this wheel slowly to the right until the 4WS indicator light comes on This action places the main rear steering angle sensor in the electroni
20. front or rear steering sensors require adjustment c the electronic neutral check is performed with the rear wheels fixed in the straight ahead position D the 4WS indicator light is illuminated with the engine running if the inner tie rods are loose in the rear steering actuator 431 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 432 8 While servicing and adjusting electronically controlled four wheel steering systems A the front main steering angle sensor is not adjustable B the rear main steering angle sensor is adjustable C removing the clock radio fuse erases the diagnostic trouble codes D if the 4WS light provides three long flashes followed by three short flashes in the diagnostic mode code 3 is indicated 9 While servicing and adjusting electronically controlled four wheel steering systems A in the diagnostic mode the 4WS indicator light flashes quickly for 10 seconds between the main and sub processor DTCs B aDTC may be set in the processor memory if the steering wheel is tumed with a rear wheel against a curb and the engine running ASE Challenge Questions 1 While discussing electronic 4WS Technician A says jumping the two terminals of the service check connector with the engine off will display DTCs Technician B says jumping the service check connector then starting the engine displays the processor in which the codes are stored Who is correct A A only B B only c Both A
21. he 4WS indicator light blink quickly for three seconds to indicate a separation between the main and sub processor codes Yes No AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 11 Did the 4WS indicator light pause for 1 6 seconds Yes No AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 12 List the sub processor DTCs displayed after the pause in step 11 and include the DTC interpretation 1 2 3 13 Did the 4WS indicator light pause for 3 seconds and then repeat the cycle Yes No AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 14 On the basis of all the DTCs displayed state the required diagnostic procedure to locate the exact cause of the defect s and explain the reasons for your diagnosis Instructor s Response 434 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 435 p Job Sheet 40 Name Date Remove and Replace Rear Steering Actuator Upon completion of this job sheet you should be able to remove and replace a rear steering actuator ASE Correlation This job sheet is related to ASE Automotive Suspension
22. he ignition is turned from OFF to ON while driving OOOO O wN o The car is driven aggressively with the driver and three passengers on board or the steering wheel is turned with a rear wheel blocked by the curb etc The engine is started while quick charging the battery pe 74 Driving the car with the parking brake ON ON 5 minutes after detection Figure 13 3 Codes that represent problems caused by abnormal or harsh driving conditions SERVICE TIP Do not attempt to disassemble the rear steering actuator other than tie rods tie rod ends and sensors This actuator is serviced as an assembly Because individual parts for the actuator are not available disassembly is a waste of time CAUTION Use the tie rod end removal tool carefully to avoid damage to the tie rod boot WARNING When turning the front wheels on a car with 4WS keep your hands away from the rear steering mechanism and rear wheels to avoid hand injuries Follow these steps to remove the rear steering actuator 1 Raise the vehicle on a hoist or lift the rear of the vehicle with a floor jack and sup port the chassis with safety stands placed in the vehicle manufacturer s recommended locations 2 Remove the cotter pin and nut from each tie rod end 3 Install a 12 millimeter mm nut on each tie rod end until the nuts are flush with the tie rod stud 4 Install the special tool on the tie rod end and with the tool arms parallel tighten the screw on the
23. he service check connector terminals is grounded the 4WS system enters the diagnostic mode Who is correct A A only c Both A and B B B only D Neither A nor B 4 While discussing trouble code diagnosis Technician A says many 4WS system trouble codes are cancelled when the ignition switch is turned off Technician B says codes representing problems caused by abnormal or harsh driving conditions do not illuminate the 4WS indicator light Who is correct A A only c Both A and B B B only D Neither A nor B 5 While discussing rear steering actuator service Technician A says the rear steering actuator is a replacement unit except for tie rods and sensors Technician B says the arrows on the rear steering actuator brackets must face downward Who is correct A A only c Both A and B B B only D Neither A nor B All of these statements about rear steering actuators and actuator service are true EXCEPT A Axial impact on the shaft screw may damage the actuator B Rotational force on the shaft screw may damage the actuator C The engine may be started with the rear steering lock pin in place D The shaft screw must be held with a special tool while loosening the tie rods While servicing and adjusting electronically controlled four wheel steering systems A the steering center lock pin must be installed in the left rear tie rod for many 4WS adjustments B the electronic neutral check determines if the
24. indicator light MIL replaces other terms for computer system indicator lights The four wheel steering control unit enters the fail safe mode if a defect occurs in the system In this mode the rear wheels move to the centered position Knowles SM Ch_13 qxd 9 14 02 Classroom Manual Chapter 13 page 310 3 30 PM Page 410 F Damper Control When the 4WS control unit enters the fail safe mode a quick return of the rear wheels to the straight ahead position would adversely affect steering under certain steering wheel and rear wheel positions To prevent this action the 4WS control unit energizes the damper relay when it enters the fail safe mode The rear steering actuator motor is spun by the steering shaft move ment as this shaft is moved to the centered position by centering spring force This action causes the motor armature to act as a voltage generator The voltage generated by the armature is fed back through the damper relay to the motor armature Under this condition the motor rotation is slowed and the retum spring slowly moves the rear steering shaft to the straight ahead position Without the action of the damper relay the return spring would move the rear steering shaft quickly to the straight ahead position Trouble Code Diagnosis Road Test CUSTOMER CARE While discussing customers automotive problems always remain polite and never make statements that make customers feel uninformed about their vehicles
25. ing harness connector Loosen the front sub steering angle sensor locknut then tighten the locknut fully by hand Back this locknut off three quarters of a turn and connect the connector Be sure the front wheels are in the straight ahead driving position and tum the steer ing wheel until the 4WS indicator light is illuminated Keep the steering wheel in this position Slowly turn the front sub steering angle sensor clockwise until the 4WS indicator light goes off and then mark the sensor position in relation to the housing Slowly rotate the front sub steering angle sensor counterclockwise until the 4WS indi cator light begins to blink and then mark the sensor in relation to the housing Fig ure 13 35 Set the front sub steering angle sensor in the center of the range from where the light went off to where the light began to blink Hold the sensor in this position and tighten the locknut to the specified torque Turn off the ignition switch If the front sub steering angle sensor harness is twisted disconnect the connector and straighten the harness Install the harness in the clamp and install the sensor cover Secure the cover with a new tie strap Perform the electronic neutral check described earlier in this chapter Rear Sub Steering Angle Sensor Adjustment The rear main steering angle sensor is not adjustable Proceed with these steps to adjust the rear sub steering angle sensor 1 2 Raise the front and rear susp
26. is O ring on the sensor Install the rear main steering angle sensor and O ring in the actuator housing with the dowel pins properly positioned and tighten the mounting bolts to the specified torque Installing Rear Steering Actuator Follow these steps for rear steering actuator installation 1 Rear steering actuator Install the rear steering actuator and the four mounting bolts and bracket The arrow on the bracket must face upward Figure 13 22 Tighten the rear steering actuator mounting bolts to the specified torque CAUTION Tighten the castelated nut on the tie rod ends to the specified torque and then tighten these nuts enough to align the slots in the nut with the hole in the tie rod pin Do not loosen the nut to align the nut slots with the tie rod pin hole If this nut is loosened to align the slot with the hole the tie rod end may become loose in service Reconnect the tie rod ends to the steering arms and tighten the castelated nut to the specified torque If necessary tighten the nut slightly to align the nut slots with the tie rod pin hole Install the cotter pin in the nut and tie rod end pin openings and bend one leg of the cotter pin downward over the nut Bend the other cotter pin leg upward over the top of the tie rod end pin Figure 13 23 Check all the wiring connectors for contamination and clean as necessary Install all the wiring connectors on the rear steering actuator and tighten all the terminal
27. ith the holding tool and loosen the tie rod with a wrench 10 Thread the tie rod off the shaft screw and repeat this procedure on each tie rod end CAUTION Do not allow dust dirt or foreign material to enter the tie rod end ball joint or boot This contamination causes rapid component wear CAUTION Never apply axial impact or rotational force to the shaft screw in the rear steering actuator Either of these actions may cause internal actuator damage Install the tie rod ends so the marks on the tie rod ends locknuts and tie rods are aligned and tighten the tie rod locknuts to the specified torque Marks on tie rod ends locknuts and tie rods properly aligned Yes No Specified tie rod end locknut torque Actual tie rod end locknut torque Instructor check Screw each inner tie rod onto the shaft screw while holding the lock washer so its tabs are in the inner tie rod end The stop washer must be installed on the shaft screw with the chamfered side facing outward Is the stop washer properly installed with chamfered side facing outward Yes No Instructor check Drive the special holding tool between the actuator housing and the stop washer with a soft hammer Hold the shaft screw with the holding tool and tighten the inner tie rod end to the specified torque Specified inner tie rod end torque Actual inner tie rod end torque Bend the lock washer tabs against the fla
28. low all the service precautions recommended in the vehicle manufacturer s ser vice manual If these precautions are not followed electronic components may be damaged Always follow the exact 4WS service and diagnostic procedures in the vehicle manufacturer s ser vice manual These procedures vary depending on the make and year of the vehicle 410 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 411 F The following are typical procedures for a Honda Prelude These procedures should be avoided until after the diagnosis is complete because any of these procedures will erase trouble codes 1 Disconnect the battery terminals 2 Disconnect the 4WS control unit connector 3 Remove the number 43 clock radio 10 A fuse from the underhood fuse relay box Follow these steps to obtain the trouble codes 1 Remove the dual terminal service check connector located behind the center When the two ter console and connect the two terminals in this connector with a jumper wire minals on the service Figure 13 1 check connector are 2 Turn on the ignition switch but do not start the engine connected together the 4WS computer supplies flash codes on the 4WS indicator light 3 Observe the 4WS indicator light to read the trouble codes Three longer flashes fol lowed by a brief pause and one quicker flash indicates code 31 The codes are given in numerical order 4 Record the fault codes Trouble Code Display with Engine Running The 4
29. mmeter reading went to infinite while wiggling the wires indicating an intermittent open circuit The technician replaced the rear sub steering angle sensor and performed the electronic neutral check and the rear sub steering angle sensor adjustment During a road test the AWS indicator light did not come on 430 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 431 p Terms to Know Cable reel Front sub steering angle sensor Rear sub steering angle sensor Fail safe mode Rear main steering angle sensor Service check connector Front main steering angle sensor Rear steering center lock pin ASE Style Review Questions 1 While discussing the fail safe function Technician A says the 4WS indicator light is illuminated during the fail safe function Technician B says the rear wheels steer normally when the 4WS control unit enters the fail safe mode Who is correct A A only c Both A and B B B only D Neither A nor B 2 While discussing the fail safe function and damper control Technician A says the rear wheels move instantly to the centered position when the 4WS control unit enters the fail safe mode Technician B says the return spring moves the rear wheels away from the centered position Who is correct A A only c Both A and B B B only D Neither A nor B 3 While discussing trouble code diagnosis Technician A says the 4WS system service check connector is located under the driver s seat Technician B says when one of t
30. nter lock pin until it bottoms in the actuator Figure 13 28 3 Position the front wheels in the straight ahead position to prevent the rear wheels from steering if the engine is started by mistake 4 Turn the ignition switch on and push the left rear wheel fully to the right by hand then push this wheel fully to the left by hand while a coworker observes the 4WS 423 ae Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 424 F Sealing washer L bolt Rear steering center lock pin Figure 13 28 Removing the rear cap bolt and sealing washer and installing the rear steering center lock pin indicator light Figure 13 29 The 4WS indicator light should begin to flash at 0 2 second intervals when the left rear wheel is pushed to the left a small amount If the 4WS indicator light does not flash adjust the rear sub steering angle sensor 5 With the ignition switch on push the left rear wheel fully to the left by hand then slowly push it to the right The 4WS indicator light should be illuminated for more than two seconds when the left rear wheel is pushed to the right Figure 13 30 If the AWS indicator light is not illuminated remove the rear main steering angle sensor and check it for damage 6 Turn off the ignition switch 7 Remove the rear steering center lock pin and install the cap bolt and washer Tighten the cap bolt to the specified torque 8 Remove the jumper wire from the service check connector 9 In
31. nuts to the specified torque Figure 13 24 Install the terminal cover on the rear main steering sensor terminals Remove the rear steering lock pin and install the cap bolt and washer Leave the steering actuator cover removed until after the final rear steering actuator adjustments Cotter pin on reassembly bend the cotter pin as shown Castelated nut Mounting bolts Mounting Tie rod bracket end Figure 13 22 Installing the rear steering actuator Figure 13 23 Proper installation of cotter pin in the mounting screws and bracket tie rod end 420 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 421 F connector Main connector gt 3 P connector Figure 13 24 Installing wiring connectors on the rear steering actuator Rear Steering Actuator Adjustment Electronic Neutral Check Preliminary Checks If the power to the 4W S control unit has been shut down for any of the following operations start the engine and turn the steering wheel fully right and left 1 Battery cables have been disconnected 2 The 4WS control unit connector has been disconnected 3 The number 43 clock radio fuse has been disconnected CAUTION Do not start the engine with the rear steering actuator lock pin in place This action may damage the lock pin and rear steering actuator Prior to the electronic neutral check be sure the steering wheel spoke is at the designated angle while driving straight ahead Be sure the rear
32. o not start the engine h 3 Observe the 4WS indicator light to read the diagnostic trouble codes DTCs Three h longer flashes followed by a brief pause and one quicker flash indicates code 31 The codes are given in numerical order 4 List the DTCs provided with ignition switch on and the engine not running and include the DTC interpretation 1 2 3 5 Tum the ignition switch off and start the engine while observing the 4WS indicator light h in the instrument panel 6 Does the 4WS indicator light blink once quickly when the ignition switch is tumed on AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 433 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 434 p Task Completed 7 After the quick flash in step 6 did the 4WS indicator light pause for three seconds AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 8 List the main processor DTCs displayed after the pause in step 7 and include the DTC interpretation 1 2 3 9 Did the 4WS indicator light pause for 1 6 seconds after the DTCs displayed in step 8 Yes 1 No AWS light operation Satisfactory Unsatisfactory If the 4WS light operation is unsatisfactory describe the light operation 10 Did t
33. only C Both A and B D Neither A norB While discussing electronic 4WS Technician A says that after repairing a defect of the main steering angle sensor in the Honda Prelude AWS system fuse 43 must be removed to cancel the code Technician B says the battery terminal must be removed to cancel DTCs in parts of the Honda Prelude 4WS system other than the main steering angle sensor Who is correct A A only B B only C Both A and B D Neither A norB 432 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 433 p Job Sheet 39 Name Date Retrieve Diagnostic Trouble Codes DTCs Four Wheel Steering 4WS System Upon completion of this job sheet you should be able to retrieve diagnostic trouble codes DTCs on four wheel steering 4WS systems ASE Correlation This job sheet is related to ASE Automotive Suspension and Steering Task Inspect diagnose ad just service or replace components of electronically controlled steering systems Tools and Materials Jumper wire Describe the Vehicle Being Worked On Year Make Model VIN Engine type and size Procedure Task Completed 1 Be sure the ignition switch is off and remove the dual terminal service check connector located behind the center console Connect the two terminals in this connector with a jumper wire Is the jumper wire properly connected Yes No Instructor check 2 Tum the ignition switch on but d
34. operly aligned push the steering wheel down bag module on top of into place and install the retaining nut the steering wheel to the air bag electrical system while allowing steering wheel rotation Front Sub Steering Angle Sensor Adjustment 8 Hold the steering wheel and tighten the retaining nut to the specified torque Use this procedure for the front sub steering angle sensor adjustment 1 Raise the front and rear suspension with a floor jack and place safety stands under the proper chassis locations specified by the car manufacturer All four wheels must be off the floor Steering Cable wheel Air bag module Figure 13 33 Proper alignment of the steering wheel openings and cable reel pins 426 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 427 F Front sub steering angle sensor Wire tie replace p Figure 13 34 Cutting the tie strap and removing the front sub steering angle sensor cover 2 Set the steering wheel in the straight ahead driving position 3 Connect a jumper wire across the 4WS system service check connector terminals 4 Pull the parking brake on fully and turn on the ignition switch Be sure the parking brake warning light is illuminated 5 Turn the ignition switch off 10 11 12 13 Cut the tie strap off the front sub steering angle sensor cover and remove this cover Figure 13 34 Remove the wiring harness from the clamp and disconnect the wir
35. peration and indicator light check all electrical connectors on the service check connector behind the cen front steering gear and rear steering ter console actuator P13 4 Look up the diagnostic procedure P13 5 Connect a jumper wire between P13 6 Turn on the ignition switch and trouble codes in the car manufac the terminals in the service check con turer s service manual nector P13 7 Observe the 4WS indicator light P13 8 Turn off the ignition switch P13 9 Remove the jumper wire from the flashes to obtain the fault codes service check connector A29 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 430 p CASE STUDY A customer complained about the 4WS indicator light coming on intermittently on a Honda Prelude with an electronic 4WS system The technician asked the customer about any other steering problems and the customer reported the car steered normally The technician road tested the car but the 4WS light did not come on which indicated there were no electronic problems in the system The customer was concerned about a possible safety hazard while driving this vehicle with the 4WS indicator light illuminated In reply to this concern the technician explained to the customer about the fail safe function in the 4WS system and the rear wheels being centered in this mode The technician asked the customer about any recent service work completed on the vehicle In response to this question the customer replied that the car had
36. ring center lock pin and all wiring harness connectors on the rear steering actuator 414 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 415 p Rear steering actuator Tie rod end pe S Mounting Vy bracket Wrenches bolts Figure 13 8 Removing the four mounting bolts Figure 13 9 Loosening the tie rod end locknut bracket and rear steering actuator 3 Remove the tie rod end 4 Remove the boot bands and clamps from the inner tie rod ends Figure 13 10 5 Place the flat side of the rack holding tool toward the actuator housing and drive the special rack holding tool between the actuator housing and the stop washer with a soft hammer Figure 13 11 6 Straighten the tabs on the tie rod lock washer Rack holding tool a S SERVICE TIP Hold the special holding tool firmly while loosening the tie A rod to avoid applying rotational force to the shaft screw in the actuator Tube clamp holder Figure 13 10 Removing boot bands and clamps from Figure 13 11 Installing the special rack holding tool the inner tie rod end between the actuator housing and the stop washer 415 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 416 F holder Figure 13 12 Removing the tie rod from the shaft screw 7 Hold the shaft screw with the holding tool and loosen the tie rod with a wrench Figure 13 12 8 Thread the tie rod off the shaft screw and repeat this procedure on each tie rod end Tie Rod En
37. stall the rear steering actuator cover AWS indicator light Rear left wheel Figure 13 29 The 4WS indicator light should flash when the left rear wheel is pushed to the left if the rear sub steering angle sensor is properly adjusted 424 ae Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 425 p AWS indicator light Rear left wheel Figure 13 30 Pushing the left rear wheel to the right and observing the 4WS indicator light checks the rear main steering angle sensor Front Main Steering Angle Sensor Adjustment Proceed as follows for the front main steering angle sensor adjustment 1 Place the car on an alignment rack with each wheel on a tuming radius gauge tum table Turn the steering wheel fully to the right and then fully to the left count the number of turns from fully right to fully left 2 Tum the steering wheel back from full left exactly one half the number of tums from fully right to fully left This action centers the front steering rack The steering wheel spoke should be within the vehicle manufacturer s specified number of degrees from the horizontal position If the steering wheel is not within this specified position pro ceed with the front main steering angle sensor adjustment and spoke angle adjustment 3 Set the steering wheel so the front wheels are straight ahead and remove the steering wheel retaining nut Use a steering wheel puller to remove the steering wheel Figure 13 31 Steering wh
38. stalled in the tie rod end nuts Yes No Instructor check Check all the wiring connectors for contamination and clean as necessary Install all the wiring connectors on the rear steering actuator and tighten all the terminal nuts to the specified torque Wiring terminal condition Satisfactory Unsatisfactory Specified wiring terminal nut torque Actual wiring terminal nut torque Install the terminal cover on the rear main steering sensor terminals Remove the rear steering lock pin and install the cap bolt and washer Leave the steering actuator cover removed until after the final rear steering actuator adjustments Is the rear steering lock pin removed Yes No Are the cap bolt and washer properly installed in the rear steering lock pin hole Instructor check 436 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 437 p Job Sheet 41 Name Date Remove and Replace Rear Steering Actuator Tie Rods and Tie Rod Ends Upon completion of this job sheet you should be able to remove and replace rear steering actuator tie rods and tie rod ends ASE Correlation This job sheet is related to ASE Automotive Suspension and Steering Task Inspect diagnose ad just service or replace components of electronically controlled steering systems Tools and Materials Torque wrench Wax marker Rack holding tool Describe the Vehicle Being Worked On Year Make Model
39. t on the inner tie rod end Are the lock washer tabs bent against the flat on the inner tie rod end Yes J No Instructor check 438 Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 439 p Task Completed 16 Remove the special holding tool and apply silicone grease to the sliding surface of the tie rod Place a light coating of silicone grease inside the tie rod boot Is the sliding surface of the tie rod propery lubricated Yes No Is the inside surface of tie rod boot properly lubricated Yes No Instructor check 17 Apply the vehicle manufacturer s recommended grease to the circumference of the h inner tie rod joint housing Is the circumference of inner tie rod joint housing properly lubricated Yes No Instructor check 18 Install the boots on the actuator housing and install the boot bands with the locking h tabs properly positioned in relation to the actuator housing Are the locking tabs properly positioned in relation to the actuator housing Yes No Instructor check CAUTION While staking the boot clamps be careful not to damage the inner tie rod boots 19 Tighten the boot bands and bend both sets of locking tabs over the band Tap lightly h on the doubled over portion of the band to reduce its height and stake the locking tabs firmly Are the boot
40. teering wheel If the 4WS indicator light comes on at a point outside of this specified range the 4WS system requires adjustment Use the following procedure to check the front sub steering angle sensor The front sub steering 1 Slowly tum the steering wheel to the left and right of the center position until the angle sensor sends a 4WS indicator light blinks at intervals of 0 2 seconds Repeat this procedure several voltage signal He the times to locate the exact steering wheel position where the indicator light begins 4WS computer in blinking The light should begin blinking within 2 2 in 55 mm to the left or ight of _ elation to rack the center mark on the steering wheel movement in the ae Ba ota front steering gear 2 If the 4WS indicator light does not begin flashing within this specified range a 4WS system adjustment is necessary After adjusting the front sub steering sensor the 4WS indicator light should begin flashing when the steering wheel is turned 0 7 in 18 mm to the left or right of the center mark on the steering wheel Rear Sensor Inspection Electronic Neutral Check Use the following procedure to complete the rear sensor inspection 1 Release the parking brake and be sure the parking brake warning light is off This causes the 4WS control unit to enter the rear steering sensor inspection mode 2 Remove the rear cap bolt and sealing washer from the rear steering actuator and install the rear steering ce
41. tool to loosen the tie rod end Figure 13 4 Repeat the procedure on both tie rod ends Tie rod end removal tool Puller A Tie rod end e NOT Figure 13 4 Removing a tie rod end with a special tool 413 a Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 414 F Chassis Rear steering actuator Cover Figure 13 5 Removing the rear steering actuator cover 5 Remove the nuts from the tie rods and remove the tie rods from the steering arms 6 Remove the rear steering actuator cover Figure 13 5 The rear steering 7 Remove the cap bolt and washer and install the rear steering center lock pin center lock pin locks Figure 13 6 the rear steering in the 8 Remove the ground cable connector and all wiring hamess connectors on the rear centered position for test and service purposes steering actuator Figure 13 7 9 Remove the four mounting bolts and bracket and remove the rear steering actuator Figure 13 8 Tie Rod and Tie Rod End Removal Follow these steps for tie rod and tie rod end removal 1 Mark the relative position of the tie rod end locknut and tie rod with a wax marker 2 Hold the tie rod end with a wrench and loosen the locknut Figure 13 9 Ground Sealing washer Cap bolt connector Rear steering Main center lock pin connector connector Figure 13 6 Removing the cap bolt and washer and Figure 13 7 Removing the ground cable connector installing the rear stee
42. wheels are in the straight ahead driving posi tion before the electronic neutral check Steering Wheel Marking and Diagnostic Mode Entry Follow these steps to mark the steering wheel and enter the front steering sensor diagnostic mode Special Tools 1 Drive the vehicle on an alignment rack and place all four wheels on turning radius Turning radius gauge gauge turntables Be sure the wheels are in the center of the turntables with the turntables wheels straight ahead and the turntables in the zero degree position Figure 13 25 Turning radius gauge turntable Figure 13 25 All four wheels must be on radius gauge turntables with the wheels straight ahead and the turntables in the zero degree position 421 ae Knowles SM Ch_13 qxd 9 14 02 3 30 PM Page 422 F Center mark l 55mm 2 2in 18mm 0 7in 1 from center mark from center mark 9mm 0 4in Tape Figure 13 26 Steering wheel marking for electronically neutral check 2 Place a piece of masking tape 12 in 300 mm long on top of the steering wheel Mark the tape at each of the following locations on the outer circumference of the wheel Figure 13 26 e center highest point on the wheel 0 4 in 9 mm right and left of the center mark 0 7 in 18 mm right and left of the center mark e 2 2 in 55 mm right and left of the center mark 3 Bend a stiff piece of wire so it can be taped to the top of the dash with the outer
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