35B - Evo X Service Manuals
Contents
1. light display light display Correct Faulty ABS failure Illuminates Illuminates EBD failure Illuminates Illuminates Illuminates Illuminates When scan Actuator not tool is operated connected Actuator operated Flash 2Hz _ After actuator Illuminates Illuminates operated NOTE e When the brake fluid level in the brake fluid reser e The ABS warning light and brake warning light voir tank is at a specified value or less or when remain illuminated until the ignition switch is the parking brake lever is in the operating status turned to the LOCK OFF position the brake warning light illuminates TSB Revision FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS 35B 7 CONSTRUCTION DESCRIPTION ASC ECU This ECU incorporates the ABS function EBD function ASC function and TCL function By integrating ABS ECU into the hydraulic unit no more wiring harnesses for sending signal that operates the solenoid valve and pump motor is required assuring higher reliability Self diagnostic and memory functions are inte grated into ASC ECU If any malfunction is detected by the diagnostic function ABS ECU activates a fail safe function and illuminates the ABS warning light and brake warning light NOTE The brake warning light is used as the EBD control warning light ABS HYDRAULIC PRESSURE CONTROL ABS CONTROL CYCLE Increase Hold Decrease Wheel speed Brake pressur2. ABS ECU checks if the wheel speed sensor signal is received from all the wheel speed sensors FAIL SAFE AND DIAGNOSTIC FUNCTION If any malfunction is detected by the diagnostic func tion ASC ECU illuminates the ABS warning light and brake warning light and disables the ABS and EBD controls In this case the brake is operated as a nor mal brake CONSTANT CHECK ASC ECU constantly checks the following items 1 ASC ECU 1 Performs a self diagnosis of ASC ECU 2 Checks for abnormal output voltage of G and yaw rate sensor and detects an open or short circuit in the G and yaw rate sensor 3 Checks the output voltage for G and yaw rate sensor and determines that a seizure has occurred to the G sensor when the output voltage exceeding the specified level continues for a certain period or more 2 ECU power supply Checks if ECU power supply voltage is within the operational range 3 Wheel speed sensor 1 Monitors the output current of the sensor signal wiring harness and checks for an abnormal output current open short circuit 2 Checks if there is any wheel that does not send pulse signal while the vehicle is in motion 3 Checks for an input of abnormally higher or lower wheel speed in relation to the vehicle speed 4 Pump motor solenoid valve Checks that the ASC ECU output signal and the operating statuses of pump motor and solenoid valve agree with each other Also ASC ECU has the following functio
3. Detects the steering angle of steering wheel and outputs the signal to ASC ECU via the CAN bus line Master cylinder pressure sensor Wheel cylinder pressure sensor Integrated into the hydraulic unit converts the signal of brake fluid pressure in master cylinder to the voltage value then outputs the value to ASC ECU Integrated into the hydraulic unit converts the signal of brake fluid pressure in wheel cylinder of each wheel to the voltage value then outputs the value to ASC ECU Actuator Hydraulic unit Drives the solenoid valve using the signal from ASC ECU and controls the brake fluid pressure for each wheel ABS warning light Informs the driver of the system status by illuminating flashing or turning off the warning light according to the signal from ASC ECU ABS warning display Informs the driver of the system status by illuminating or turning off the warning light according to the signal from ASC ECU Brake warning light Brake warning display Used as the warning light for the parking brake brake fluid level and EBD control Informs the driver of the system status by illuminating or turning off the warning light according to the signal from ASC ECU Used as the warning light for the brake fluid level and EBD control Informs the driver of the system status by illuminating or turning off the warning light according to the signal from ASC ECU Data link connector Outputs
4. 35B 1 GROUP 35B FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS CONTENTS GENERAL DESCRIPTION 35B 2 ACTUATORS aan 35B 6 PSCECU rer 35B 7 CONSTRUCTION DESCRIPTION 35B 5 SENSOR aso ins era 358 5 SYSTEM OPERATION 35B 9 35B 2 FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS GENERAL DESCRIPTION GENERAL DESCRIPTION M2351000101059 The ABS with EBD and brake assist that ensures EBD Electronic Brake force Distribution sys directional stability and controllability during hard tem control that can provide ideal rear wheel braking has been equipped as a standard brake force has been employed This ABS employs a 4 sensor system that indepen e The magnetic encoder for wheel speed detection dently controls the right and left wheels of front and has been installed instead of the rotor as the rear and has the following features wheel speed sensor e Compared with the conventional model by add e For wiring harness saving and secure data com ing the information from the G and yaw rate sen munication CAN 2 bus has been adopted asa sor master cylinder pressure sensor and wheel tool of communication with another ECU cylinder pressure sensor to the ABS control the NOTE braking performance and steering performance when driving high speed and on race circuits e 1 EBD Electronic Brake force Distribution have been improved so that the vehicle s high e 2 For more details on CAN Controller Area Net
5. athletic performance can be further demon work refer to GROUP 54C P 54C 2 strated e As with the active skid control ASC ABS is con trolled by ASC ECU SPECIFICATIONS Item Specifications ABS control type 4 sensors Wheel speed sensor Magnetic encoder Front 96 N pole 48 S pole 48 Rear 86 N pole 43 S pole 43 Type Semiconductor TSB Revision FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS 35B 3 GENERAL DESCRIPTION CONSTRUCTION DIAGRAM 10 x SERVICE REQUIRED AC708736AB TSB Revision 35B 4 FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS GENERAL DESCRIPTION MAIN COMPONENTS AND FUNCTIONS Parts name Functional description Sensor Wheel speed sensor Outputs the frequency pulse signal in proportion to the rotation speed of each wheel to ASC ECU Magnetic encoder for wheel speed detection When the magnetic encoder for wheel speed detection a plate on which north and south pole sides of the magnets are arranged alternately rotates the wheel speed sensor outputs frequency pulse signal in proportion to each wheel speed Stop light switch Outputs the signal indicating whether the brake pedal is depressed or not to ASC ECU G and yaw rate sensor Detects the yaw rate and longitudinal lateral acceleration of a vehicle then outputs the signal to ASC ECU via the CAN line Steering wheel sensor
6. e ASC ECU calculates the speed and deceleration of each wheel based on the signals from the wheel speed sensors and G and yaw rate sensors of four wheels and estimates the vehicle speed of at that time M2351003000713 e ASC ECU detects the vehicle deceleration speed using the signals of the steering wheel sensor wheel speed sensor G and yaw rate sensor master cylinder pressure sensor and wheel cylin der pressure sensor to acquire the wheel rotation status At the same time ASC ECU estimates the wheel slipping status based on the prepro grammed algorithm and then controls the sole noid valve in the hydraulic unit so that the wheels do not lock Estimated vehicle speed Actual vehicle speed AC506830AB TSB Revision 35B 8 FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS CONSTRUCTION DESCRIPTION When the brake is depressed the brake fluid pressure applied to the wheel cylinder increases and the wheel speed decreases When the difference between the wheel speed and vehicle speed increases and the vehicle deceleration exceeds the specified value Point A ASC ECU 4 When the wheel speed deceleration recovers further and passes the point C ASC ECU determines that the wheel lock possibility has been eliminated and maintains the brake fluid pressure by outputting the pressure increase signal again Between c and d determines that the wheels are about to be 5 Brake fluid pressure is controll
7. ed through the locked At this time ASC ECU reduces the brake repetition of pressure increase and pressure hold fluid pressure by outputting the pressure Between d and e decrease signal to the solenoid valves IN OUT 6 When the wheel deceleration exceeds the Between a and b threshold again ABS ECU controls the brake fluid 3 When the vehicle deceleration and wheel speed pressure by repeating the cycle Steps 2 to 5 begin to recover and when the vehicle speed reaches the point B ASC ECU outputs the pressure hold signal to maintain the wheel cylinder fluid pressure Between b and c EBD FLUID PRESSURE CONTROL EBD operating conceptual design Braking force distribution by EBD control Braking force distribution curve by the existing proportioning valve ted by one persons Ideal distribution curve when seated by fixed persons Rear braking force Braking Force Improved ET ee SS distribution curve when sea Front braking force AC208548AB EBD control is activated within the lower slip ratio area where ABS is disabled EBD calculates the vehicle deceleration and slip amount of the four wheels based on the wheel speed sensor signal If the rear wheel speed differs from the vehicle speed by a certain level or more EBD boosts holds and depressurizes the rear wheel control solenoid valve in the hydraulic unit and then adjusts the rear wheel brake fluid pressure fairly c
8. lose to an ideal distribu tion curve TSB Revision FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS 35B 9 SYSTEM OPERATION INITIAL CHECK ASC ECU performs the following initial checks using the diagnostic functions The ABS warning light illu minates for approximately 3 seconds including the initial check after the ignition switch is turned ON If any malfunction is detected ABS ECU continues illu minating the ABS warning light and disables the ABS control NOTE ABS warning light may keep illuminating after the ignition switch is turned ON until the startup vehicle speed reaches approximately 10 km h This allows as long as ASC ECU retains any diagnostic trouble code which is related to the wheel speed sensor malfunction or pump motor malfunction recorded during the previous ignition ON status ASC ECU to continue illuminating the ABS warning light until it verifies that the malfunction for that code is resolved startup check STARTUP CHECK When the startup vehicle speed reaches approxi mately 10 km h ASC ECU performs the following checks 1 Motor solenoid valve check Initial startup only Turns ON the motor relay in ECU and checks the pump motor operation At the same time ASC ECU sequentially energizes each solenoid valve for a very short period and checks the valve operation NOTE Initial startup indicates the first startup after the system has started 2 Wheel speed sensor check
9. nals in pro speed sensor mounted on the knuckle assembly and portion to the wheel speed the magnetic encoder for wheel speed detection which is press fitted together with the oil seal to the rear wheel bearing G AND YAW RATE SENSOR This sensor is installed under the instrument panel center lower and detects the yaw rate as well as the lateral and longi tudinal acceleration of the vehicle G amp yaw rate sensor ae AC613534AB TSB Revision 35B 6 FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS CONSTRUCTION DESCRIPTION STEERING WHEEL SENSOR The steering wheel sensor is mounted to the column switch and detects the rotational angle of the steering wheel ACTUATORS M2351002000475 HYDRAULIC UNIT ABS WARNING LIGHT ABS WARNING As with the active skid control ASC ABS is con DISPLAY BRAKE WARNING LIGHT trolled by ASC ECU BRAKE WARNING DISPLAY NOTE For more information on the internal hydraulic The ABS system illuminates or flashes the ABS circuit of hydraulic unit refer to GROUP 35C Sys warning light ABS warning display brake warning tem Operation P 35C 14 light or brake warning display under the following conditions and informs the driver of the ABS system status ABS warning light ABS warning display brake warning light and brake warning display illumination or flashing pattern ABS warning ABS warning Brake warning Brake warning
10. ns for easier system checks e Diagnostic trouble code set e Service data output e Actuator test SYSTEM OPERATION Refer to GROUP 35C System Operation P 35C 14 M2351004000374 TSB Revision NOTES
11. the diagnostic trouble code and establishes the communication with the scan tool ASC control unit ASC ECU Controls the actuators described above based on the signals coming from each sensor Controls the self diagnostic functions and fail safe functions Controls diagnostic function Compatible with scan tool TSB Revision FOUR WHEEL ANTI LOCK BRAKE SYSTEM 4ABS 35B 5 CONSTRUCTION DESCRIPTION SYSTEM CONFIGURATION Refer to GROUP 35C General Description P 35C 2 ABS ELECTRICAL DIAGRAM Refer to GROUP 35C General Description P 35C 2 CONSTRUCTION DESCRIPTION SENSOR M2351001000687 WHEEL SPEED SENSOR FRONT REAR Front wheel speed sensor Rear wheel speed sensor j Encoder for wheel speed detection Encoder for wheel speed detection AC507376AB The wheel speed detecting section is a kind of a The front wheel speed detecting section consists of pulse generator It consists of the magnetic encoder the front wheel speed sensor mounted on the for wheel speed detection plate on which north and knuckle and the magnetic encoder for wheel speed south pole sides of the magnets are arranged alter detection which is press fitted together with the oil nately which rotates at the same speed of the wheel seal to the front wheel bearing The rear wheel and the wheel speed sensor Semiconductor sensor speed detecting section consists of the rear wheel This sensor outputs frequency pulse sig
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