HOW TO PROCEED WITH TROUBLESHOOTING
Contents
1. va Diagnostic trouble code check by diagnostic trouble code problem symptom e Diagnostic trouble code displayed e Normal code displayed e Normal code displayed e Problem symptoms exist e Problem symptoms exist e No problem symptoms exist Troubleshooting of problem indicated Troubleshooting of each System Normal If a diagnostic trouble code was displayed in the initial diagnostic trouble code check it indicates that the trouble may have occurred in a wire harness or connector in that circuit in the past Therefore check the wire harness and con nectors See page IN 34 LEXUS 1IS300 IS200 SUP RM870E IN 28 INTRODUCTION HOWTO TROUBLESHOOT ECU CONTROLLED SYSTEMS 3 SYMPTOM SIMULATION The most difficult case in troubleshooting is when there are no problem symptoms occurring In such cases a thorough customer problem analysis must be carried out then simulate the same or similar conditions and environment in which the problem occurred in the customer s vehicle No matter how much experience a technician has or how skilled he or she may be if he or she proceeds to troubleshoot without confirming the problem symptoms he or she will tend to overlook something important in the repair operation and make a wrong guess somewhere which will only lead to a standstill For example2. with harness Bo0691 e Indicates the place to check the voltage or resistance e Indicates the connector position to be checked from the front or back side Wire Harness Check from the connector back side Check from the connector front side without harness e Indicates the condition of the connector of ECU during the check In this case care must be taken not to bend the terminals E6 Connector Connector being checked is connected Connector being checked is disconnected E6 Connector LEXUS 1S300 IS200 SUP RM870E B00972
3. Supplemental restraint system check sheet CUSTOMER PROBLEM ANALYSIS CHECK Supplemental Restraint System Check Sheet eee Customer s Name Date Vehicle BroughtIn Date Problem First Occurred went O Fine O Cloudy O Rainy O Snowy O Other O Starting O Idling Vehicle Operation O Driving O Constant speed O Acceleration O Deceleration O Other LEXUS IS300 IS200 SUP RM870E INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 25 SYSTEMS 2 SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK The diagnostic system in the LEXUS IS300 IS200 fulfills various functions The first function is the Diagnos tic Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU memory at the time of occurrence to be output by the technician during troubleshooting Another function is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly By using these check functions the problem areas can be narrowed down quickly and troubleshooting can be performed effectively Diagnostic functions are incorporated in the following systems in the LEXUS 1S300 IS200 Sister Diagnostic Trouble Input Signal Check Diagnostic Test y Code Check Sensor Check Mode Active Test 1 Engine 2JZ GE mang with Check Mode 2 Automatic Transmission A650E 2 with Check Mode 3 ABS with EBD amp BA amp TRG System Pao al AES WAN ERD ABAE TRO ASC SEN a el
4. Tc and CG terminal connection LEXUS 1IS300 IS200 SUP RM870E IN 32 INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED 6 CIRCUIT INSPECTION How to read and use each page is shown below SYSTEMS e Diagnostic Trouble Code No and Detection Item e Circuit Description The major role and operation etc of the circuit and its component parts are explained DTC B0100 13 Short in D Squib Circuit CIRCUIT DESCRIPTION v The D squib circuit consists of the airbag sensor assembly spiral cable and steering wheel pad It causes the airbag to deploy when the airbag deployment conditions are satisfied For details of the function of each components see OPERATION on page RS 2 DTC BO0100 13 is recorded when a short is detected in the D squib circuit DTC No DTC Detection Condition iS A Trouble Area Short circuit between D wire harness and D wire harness of squib B010013 D squib malfunction Spiral cable malfunction eAirbag sensor assembly malfunction Steering wheel pad D squib Spiral cable eAirbag sensor assembly Wire harness WIRING DIAGRAM Airbag Sensor Assembly D squib R16015 LEXUS 1IS300 IS200 SUP RM870E Indicates the diagnostic trouble code diagnostic trouble code set parameter and suspect area of the problem e Wiring Diagram This shows a wiring diagram o
5. 5 Supplemental Restraint System Eo o 6 Theft Deterrent System 7 Cruise Control System 8 Engine Immobiliser System 9 Body Control System 10 Multiplex Communication System O O LEXUS IS300 IS200 SUP RM870E IN 26 In diagnostic trouble code check it is very important to determine whether the problem indicated by the diag nostic trouble code is still occurring or occurred in the past but returned to normal at present In addition it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic trouble code is directly related to the problem symptom or not For this reason the diagnostic trouble codes should be checked before and after the symptom confirmation to determine the current conditions as shown in the table below If this is not done it may depending on the case result in unnecessary troubleshooting for normally operating systems thus making it more difficult to locate the problem or in repairs not pertinent to the problem Therefore always follow the procedure in correct order and perform the diagnostic trouble code check INTRODUCTION OW Ty ee ener ECU CONTROLLED EM H SYST DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE Diagnostic Trouble Code Check Make a note of and then clear Diagnostic Trouble Code Display Normal Code Display Confirmation Diagnostic Trouble Problem Condition of Symptoms Code Check Problem symptoms Same diagnostic exist trouble c
6. INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 23 SYSTEMS HOW TO PROCEED WITH TROUBLESHOOTING Carry out troubleshooting in accordance with the procedure on the following page Here only the basic pro cedure is shown Details are provided in Diagnostics section showing the most effective methods for each circuit Confirm the troubleshooting procedures first for the relevant circuit before beginning troubleshooting of that circuit Vehicle Brought to Workshop y 1 1 Customer Problem Ask the customer about the conditions and the Analysis environment when the problem occurred 2 _ Symptom Confirmation 3 and Diagnostic Trouble Symptom Simulation Code Check diii 2 3 Confirm the symptoms and the problem condi tions and check the diagnostic trouble codes When the problem symptoms do not appear dur ing confirmation use the symptom simulation method described later on Si 4 Diagnostic Trouble Code Chart NZ Problem Symptoms Table 4 5 6 Check the results obtained in Step 2 then confirm the inspection procedure for the system or the part which should be checked using the diagnostic 6 Circuit Inspection or Parts trouble code chart or the problem symptoms table Inspection 7 Repair Check and repair the affected system or part in accordance with the instructions in Step 6 qi 8 After completing repairs confirm that the prob
7. f the circuit Use this diagram together with ELECTRICAL WIR ING DIAGRAM to thoroughly understand the cir cuit Wire colors are indicated by an alphabetical code B Black L Blue R Red BR Brown LG Light Green V Violet G Green O Orange W White GR Gray P Pink Y Yellow SB Sky Blue The first letter indicates the basic wire color and the second letter indicates the color of the stripe B00803 INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 33 SYSTEMS _ LOCK START D Ignition Switch LOCK OFF A Ignition Switch START Indicates the position of the ignition switch during the check Inspection Procedure ON A Ignition Switch ON if the circuit is normal or abnormal and if it ACC r A Ignition Switch ACC problem is located in the sensors actuators Use the inspection procedure to determine is abnormal use it to determine whether the wire harness or ECU INSPECTION PROCEDURE y 2 Check voltage at IG2 and ACC of airbag sensor assembly AB0119 W02766 f R Y TAE 0008 oo goo0 ON Airbag Sensor Assembly IG2 H00041 OK PREPARATION Turn ignition switch ON CHECK Measure voltage between terminals IG2 and ACC of airbag sensor assembly and body ground OK Voltage Below 16 V NG Check battery and charging system See charging system section
8. for a problem which only occurs when the engine is cold or for a problem which occurs due to vibration caused by the road during driving etc the problem can never be determined so long as the symptoms are confirmed with the engine hot condi tion or the vehicle at a standstill Since vibration heat or water penetration moisture is likely to cause prob lem which is difficult to reproduce the symptom simulation tests introduced here are effective measures in that the external causes are applied to the vehicle in a stopped condition Important Points in the Symptom Simulation Test In the symptom simulation test the problem symptoms should of course be confirmed but the problem area or parts must also be found out To do this narrow down the possible problem circuits according to the symp toms before starting this test and connect a tester beforehand After that carry out the symptom simulation test judging whether the circuit being tested is defective or normal and also confirming the problem symp toms at the same time Refer to the problem symptoms table for each system to narrow down the possible causes of the symptom Ea VIBRATION METHOD When vibration seems to be the major cause CONNECTORS Slightly shake the connector vertically and horizontally WIRE HARNESS Slightly shake the wire harness vertically and horizontally The connector joint fulcrum of the vibration and body through portion are the major areas to be checked thoroug
9. h ly PARTS AND SENSOR Apply slight vibration with a finger to the part of the sensor considered to be the problem cause and check that the mal function occurs HINT Applying strong vibration to relays may result in open relays 07268 LEXUS 1IS300 IS200 SUP RM870E INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 29 SYSTEMS Lad HEAT METHOD When the problem seems to occur when the suspect area is heated Heat the component that is the likely cause of the malfunction with a hair dryer or similar object Check to see if the malfunction occurs NOTICE 1 Do not heat to more than 60 C 140 F Temperature is limited not to damage the components 2 Do not apply heat directly to parts in the ECU WATER SPRINKLING METHOD When the malfunction seems to occur on a rainy day or ina high humidity condition Sprinkle water onto the vehicle and check to see if the malfunc tion occurs NOTICE 1 Never sprinkle water directly into the engine compart ment but indirectly change the temperature and hu midity by applying water spray onto the radiator front surface 2 Never apply water directly onto the electronic compo nents HINT If a vehicle is subject to water leakage the leaked water may contaminate the ECU When testing a vehicle with a water leak age problem special caution must be taken Turn on all electrical loads including the heater blower head lights rear window defogger etc a
10. iagnostic system even though the problem symptom is present it is considered that the problem is occurring outside the detection range of the diagnostic system or that the problem is occurring in a system other than the diagnostic system e Page Indicates the page where the flow chart for each circuit is located Circuit Inspection Inspection Order Indicates the circuit which needs to be checked for each problem symptom Check in the order indicated by the numbers Circuit or Part Name Problem Symptom Indicates the circuit or part which needs to be checked PROBLEM SYMPTOMS TABL Proceed with troubleshooting of each circuit in the table below Y N Symptom Suspected Area See page Withthe ignition switch in the ACC or ON position the SRS warning light sometimes lights up after approx 6 seconds have elapsed SRS warning light is always lit up even when ignition switch is in the LOCK position SRS warning light circuit Always lights up when ignition switch is in LOCK DI 180 position RASS ane af SRS warning light circuit With the ignition switch in the ACC or ON position the SRS warn Dose notlight up when ignition switch is turned to ing light does not light up ee i HN j 3 DI 183 DTC is not displayed SRS warning lightis always litup atthe time of DTC check proce ME d re Tc terminal circuit DI 187 DTC is displayed without
11. irbag sensor assembly e Open in D squib circuit B0101 14 DI 124 Steering wheel pad squib Spiral cable e Airbag sensor assembly e Wire harness ON Short in D squib circuit to ground Bo102 11 DI 128 Steering wheel pad squib Spiral cable e Airbag sensor assembly e Wire harness ON Short in D squib circuit to B B0103 12 DI 132 Steering wheel pad squib Spiral cable e Airbag sensor assembly e Wire harness ON B0105 53 Short in P squib circuit DI 136 e Front Passenger airbag assembly squib e Airbag sensor assembly e Wire harness ON e Open in P squib circuit e Front Passenger airbag assembly squib e Airbag sensor assembly e Wire harness p circuit to Ground LEXUS 1IS300 IS200 SUP RM870E e Front Passenger airbag assembly squib e Airbag sensor assembly e Wire harness INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 31 SYSTEMS 5 PROBLEM SYMPTOMS TABLE The suspected circuits or parts for each problem symptom are shown in the table below Use this table to troubleshoot the problem when a Normal code is displayed in the diagnostic trouble code check but the problem is still occurring Numbers in the table indicate the inspection order in which the circuits or parts should be checked HINT When the problem is not detected by the d
12. lem has been eliminated If the problem is not reproduced perform the confirmation test under the same conditions and in the same environment as when it occurred for the first time 8 Confirmation Test n iE LEXUS IS300 IS200 SUP RM870E IN 24 INTRODUCTION HOWTO TROUBLESHOOT ECU CONTROLLED SYSTEMS 1 CUSTOMER PROBLEM ANALYSIS In troubleshooting the problem symptoms must be confirmed accurately and all preconceptions must be cleared away in order to give an accurate judgement To ascertain just what the problem symptoms are it is extremely important to ask the customer about the problem and the conditions at the time it occurred Important Point in the Problem Analysis The following 5 items are important points in the problem analysis Past problems which are thought to be unrelated and the repair history etc may also help in some cases so as much information as possible should be gathered and its relationship with the problem symptoms should be correctly ascertained for reference in troubleshooting A customer problem analysis table is provided in Diagnostics section for each system for your use Important Points in the Customer Problem Analysis e What Vehicle model system name e When Date time occurrence frequency e Where Road conditions e Under what conditions Running conditions driving conditions weather conditions e How did it happen Problem symptoms Sample
13. nd check to see if the mal function occurs B02390 LEXUS 1IS300 IS200 SUP RM870E IN 30 INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS 4 DIAGNOSTIC TROUBLE CODE CHART The inspection procedure is shown in the table below This table permits efficient and accurate troubleshoot ing using the diagnostic trouble codes displayed in the diagnostic trouble code check Proceed with trouble shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the diagnostic trouble codes displayed The Supplemental Restraint System diagnostic trouble code chart is shown below as an example e DTC No Indicates the diagnostic trouble code e Page or Instructions instructions for checking and repairs Indicates the page where the inspection proce dure for each circuit is to be found or gives Trouble Area the problem Indicates the suspect area of e Detection Item Indicates the system of the problem or contents of the problem DIAGNOSTIC TROUBLE COD CHART If a malfunction code is displayed during the DTC check check the circuit for that code listed in the table below Proceed to the page given for that circuit e Wire harness DTC No SRS Seelpage Detection Item Trouble a Warming Light y Short in D squib circuit Steering wheel pad squib B0100 13 Spiral cable ON DI 119 e A
14. ode is displayed Problem is still occurring in the diagnostic circuit Normal code is The problem is still occurring in a place displayed other than in the diagnostic circuit The diagnostic trouble code displayed first is either for a past problem or it is a secondary problem No problem The problem occurred in the diagnostic Symptoms exist circuit in the past Problem symptoms Normal code is The problem is still occurring in a place exist displayed other than in the diagnostic circuit No problem Normal code is The problem occurred in a place other symptoms exist displayed than in the diagnostic circuit in the past LEXUS 1IS300 IS200 SUP RM870E INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED IN 27 SYSTEMS Taking into account the points on the previous page a flow chart showing how to proceed with troubleshoot ing using the diagnostic trouble code check is shown below This flow chart shows how to utilize the diagnos tic trouble code check effectively then by carefully checking the results indicates how to proceed either to diagnostic trouble code troubleshooting or to troubleshooting of problem symptoms table Diagnostic trouble code check L Making a note of and clearing of the diagnostic trouble codes displayed 4 Symptom confirmation Problem symptoms No problem symptoms exist exist Simulation test using the symptom simulation methods
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