Adaptive Variable Suspension System (Diagnostics - Introduction): Diagnosis Lexus GS III facelift

HOW TO PROCEED WITH TROUBLESHOOTING

HINT

Step 3, 4, 5, 6, 12, 15

Diagnostic steps permitting the use of Techstream.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CUSTOMER PROBLEM ANALYSIS NEXT: Go to next step
3. CHECK CAN COMMUNICATION SYSTEM Check for output DTCs. HINT: The ECU of this system is connected to the CAN communication system. Therefore before starting troubleshooting, make sure to check that there is no trouble in the CAN communication system. --> CAN COMMUNICATION SYSTEM DTC IS OUTPUT: PROCEED TO CAN COMMUNICATION SYSTEM --> NO CAN COMMUNICATION SYSTEM DTC IS OUTPUT: GO TO STEP 4
4. CHECK MULTIPLEX COMMUNICATION SYSTEM Check for output DTCs. HINT: The absorber control ECU sends the signals from each indicator light to the gateway ECU via CAN communication, and the gateway ECU sends the signals to the combination meter assembly via the multiplex communication system (BEAN). --> MULTIPLEX COMMUNICATION SYSTEM DTC IS OUTPUT: PROCEED TO MULTIPLEX COMMUNICATION SYSTEM --> NO MULTIPLEX COMMUNICATION SYSTEM DTC IS OUTPUT: GO TO STEP 5
5. CHECK DTCS NEXT: Go to next step
6. CLEAR DTCS NEXT: Go to next step
7. PROBLEM SYMPTOMS CONFIRMATION --> SYMPTOM DOES NOT OCCUR (Go to step 8) --> SYMPTOM OCCUR (Go to step 9)
8. SYMPTOM SIMULATION NEXT: Go to next step
9. CHECK DTC --> NORMAL CODE (Go to step 10) --> MALFUNCTION CODE (Go to step 11)
10. PROBLEM SYMPTOMS TABLE NEXT: Go to next step
11. DTC CHART NEXT: Go to next step
12. CIRCUIT INSPECTION NEXT: Go to next step
13. IDENTIFICATION OF PROBLEM NEXT: Go to next step
14. REPAIR NEXT: Go to next step
15. CONFIRMATION TEST NEXT --> END

Scheme 1

Scheme 2

Scheme 3

1. CHECK ABSORBER CONTROL ACTUATOR OPERATION Using the SST, connect the terminals TS and CG of the DLC3. SST: 09843-18040 Start the engine. Check that the absorber control indicator light is blinking in Test Mode. HINT: If the absorber control indicator light does not blink, inspect the absorber control indicator light circuit and TS and CG terminal circuit. Trouble area See procedure Absorber control indicator light (Remains on) Refer to «Absorber Control Indicator Light Remains ON»(ref-382797-S15098386642011012800000) Absorber control indicator light (Does not come on) Refer to «Absorber Control Indicator Light does not Come ON»(ref-382797-S23588834012011012800000) TS and CG terminal circuit Refer to «TS and CG Terminal Circuit»(ref-382797-S05421193472011012800000) Check absorber control actuator operation. Starting from the above mentioned position, as the brake pedal is depressed, the absorber control actuator position will increase by 2 steps (1 (SOFT) --> 3 --> 5 --> 7 --> 9 --> 11 --> 15 --> 17 (HARD)). At this time, bounce the vehicle and check that the shock absorber is becoming harder. HINT: To hold the absorber control actuator at a specific position, adjust it using the above mentioned procedure, then increase the vehicle speed to 3 mph (5 km/h). After that, the absorber control actuator position does not change until the engine switch is turned off. If the absorber control actuator does not operate, inspect the absorber control actuator circuit and absorber control actuator installation condition. Trouble area See procedure Absorber control actuator circuit Refer to «DTC C1725: Front Damping Force Control Actuator RH Circuit; DTC C1726: Front Damping Force Control Actuator LH Circuit; DTC C1727: Rear Damping Force Control Actuator RH Circuit; DTC C1728: Rear Damping Force Control Actuator LH Circuit»(ref-382797-S25011625642011012800000) Absorber control actuator installation condition Refer to «INSTALLATION - Step 2»(ref-382575-S00532040232011012800000) Refer to «INSTALLATION - Step 2»(ref-382575-S23815101742011012800000) Turn the engine switch off. Remove the SST from terminal TS and CG of the DLC3. Turn the engine switch on (IG). HINT: If the engine switch remains on (IG) after the SST is removed from DLC3, the vehicle will remain in the previously initialized Test Mode.

Scheme 4

1. INDICATOR LIGHT CHECK When the engine switch is turned on (IG), check that the absorber control indicator light will come on for approximately 2 seconds. (Absorber control switch is in the "NORMAL" position.) HINT: If the absorber control ECU stores any DTCs, the absorber control indicator light will come on. If the absorber control indicator light remains on or does not come on, proceed to troubleshooting for the indicator light circuit below. Trouble area See procedure Absorber control indicator light (Remains on) Refer to «Absorber Control Indicator Light Remains ON»(ref-382797-S15098386642011012800000) Absorber control indicator light (Does not come on) Refer to «Absorber Control Indicator Light does not Come ON»(ref-382797-S23588834012011012800000)
2. SENSOR SIGNAL CHECK BY TEST MODE (SIGNAL CHECK) HINT: If the engine switch is turned from on (IG) to on (ACC) or off during Test Mode (SIGNAL CHECK), all Test Mode DTCs will be erased. During Test Mode (SIGNAL CHECK), the absorber control ECU records all Test Mode DTCs. By performing the Test Mode (SIGNAL CHECK), the codes will be erased if normality is confirmed. The remaining codes will be the codes where an abnormality was found. Procedure for Test Mode. Turn the engine switch off. Connect Techstream to the DLC3. Turn the engine switch on (IG). Set Techstream to Test Mode (select "SIGNAL CHECK"). HINT: Refer to Techstream operator's manual for further details. Start the engine without depressing the brake pedal. Check that the absorber control indicator light is blinking in Test Mode. HINT: If the absorber control indicator light does not blink, inspect the absorber control indicator light circuit. Trouble area See procedure Absorber control indicator light (Remains on) Refer to «Absorber Control Indicator Light Remains ON»(ref-382797-S15098386642011012800000) Absorber control indicator light (Does not come on) Refer to «Absorber Control Indicator Light does not Come ON»(ref-382797-S23588834012011012800000)
3. PERFORM SIGNAL CHECK BY TEST MODE (SIGNAL CHECK) HINT: The "SPORT" indicator (absorber control indicator light) comes on for 1 second when inputting each diagnostic signal. Keep the absorber control switch in the "NORMAL" position. Keep the vehicle stationary on a level surface for 1 second or more (Acceleration sensor check). Turn the absorber control switch from the "NORMAL" to "SPORT" position and return to the "NORMAL" position. (An absorber control switch signal will be input.) INPUT SIGNAL TABLE Test Mode DTC Test Signal C1787 Absorber control switch operation (When the mode change signal is input.) C1791 Right front acceleration sensor signal (When the vehicle is stopped on a level road for 1 second or more.) C1792 Left front acceleration sensor signal (When the vehicle is stopped on a level road for 1 second or more.) C1793 Rear acceleration sensor signal (When the vehicle is stopped on a level road for 1 second or more.)
4. READ DTC Read the DTC(s) by following the tester screen. HINT: See the list of Test Mode DTCs.
5. RESULT Result Result Operation Test Mode DTC is output Repair the output DTC and enter the Test Mode (SIGNAL CHECK) again Test Mode DTC is not output Test Mode (SIGNAL CHECK) is complete
6. END OF SENSOR CHECK Clear the DTCs. Refer to «DTC CHECK / CLEAR»(ref-382796-S22692056532011012800000) . Check that absorber control indicator light blinks (Test Mode). Turn both the engine switch off and Techstream switch off.
7. TEST MODE DTC (DTC of SIGNAL CHECK) DTC No. Detection Item Trouble Area C1787 Refer to «DTC C1787: EMS Switch Circuit (Test Mode DTC)»(ref-382797-S36576374642011012800000) EMS Switch Circuit (Test Mode DTC) Absorber control switch Absorber control switch circuit Absorber control ECU C1791 Refer to «DTC C1715: Front Acceleration Sensor RH; DTC C1716: Front Acceleration Sensor LH; DTC C1717: Rear Acceleration Sensor; DTC C1791: Front Acceleration Sensor RH (Test Mode DTC); DTC C1792: Front Acceleration Sensor LH (Test Mode DTC); DTC C1793: Rear Acceleration Sensor (Test Mode DTC)»(ref-382797-S06262044502011012800000) Front Acceleration Sensor RH (Test Mode DTC) Absorber control ECU (Houses right front acceleration sensor assembly) C1792 Refer to «DTC C1715: Front Acceleration Sensor RH; DTC C1716: Front Acceleration Sensor LH; DTC C1717: Rear Acceleration Sensor; DTC C1791: Front Acceleration Sensor RH (Test Mode DTC); DTC C1792: Front Acceleration Sensor LH (Test Mode DTC); DTC C1793: Rear Acceleration Sensor (Test Mode DTC)»(ref-382797-S06262044502011012800000) Front Acceleration Sensor LH (Test Mode DTC) Left front acceleration sensor assembly Left front acceleration sensor assembly circuit Absorber control ECU C1793 Refer to «DTC C1715: Front Acceleration Sensor RH; DTC C1716: Front Acceleration Sensor LH; DTC C1717: Rear Acceleration Sensor; DTC C1791: Front Acceleration Sensor RH (Test Mode DTC); DTC C1792: Front Acceleration Sensor LH (Test Mode DTC); DTC C1793: Rear Acceleration Sensor (Test Mode DTC)»(ref-382797-S06262044502011012800000) Rear Acceleration Sensor (Test Mode DTC) Rear acceleration sensor assembly Rear acceleration sensor assembly circuit Absorber control ECU HINT: The codes in this table are output only in the test mode (SIGNAL CHECK).

PROBLEM SYMPTOMS TABLE

ADAPTIVE VARIABLE SUSPENSION SYSTEM

Scheme 5

Connector U2

Connector A52

Connector K72

Waveform 1 (Reference)

Scheme 6

Scheme 7

1. DIAGNOSIS SYSTEM Inspect the battery voltage. Battery voltage 11 to 14 V If the voltage is below 11 V, recharge the battery before proceeding. Check DLC3. The absorber control ECU uses the CAN system and ISO 9141-2 for communication. The terminal arrangement of the DCL3 complies with SAE J1962 and matches the ISO 9141-2 format. Verify the conditions listed in the table below: Symbols (Terminal No.) Terminal Description Condition Specified Condition SIL (2) - SG (5) Bus "+" line During communication Pulse generation CG (4) - Body ground Chassis ground Always Below 1 ohms SG (5) - Body ground Signal ground Always Below 1 ohms BAT (16) - Body ground Battery positive Always 11 to 14 V CANH (6) - CANL (14) HIGH-level CAN bus line Engine switch off 54 to 67 ohms CANH (6) - Battery positive HIGH-level CAN bus line Engine switch off 1 Mohms or higher CANH (6) - CG (4) HIGH-level CAN bus line Engine switch off 3 Kohms or higher CANL (14) - Battery positive LOW-level CAN bus line Engine switch off 1 Mohms or higher CANL (14) - CG (4) LOW-level CAN bus line Engine switch off 3 Kohms or higher HINT: If the Techstream display shows a communication error message when the cable of Techstream is connected to the DLC3, the engine switch is turned on (IG) and the tester is in operation, there is a problem either on the vehicle side or tester side. If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle. If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tester itself. Consult the service department listed in the tester's instruction manual. DTCs (Normal mode) DTCs are memorized in the absorber control ECU and read by using Techstream . Refer to «DTC CHECK / CLEAR»(ref-382796-S22692056532011012800000) . Test Mode (SIGNAL CHECK) By switching from normal mode into Test Mode, you can inspect the absorber control switch and each acceleration sensor . Refer to «TEST MODE PROCEDURE»(ref-382796-S09396953722011012800000) . Check the absorber control indicator light. Turn the engine switch on (IG). Check that the absorber control indicator light comes on for 2 seconds. If the indicator light check result is not normal, proceed to troubleshooting for the absorber control indicator light circuit below. Trouble area See procedure Absorber control indicator light (Remains on) Refer to «Absorber Control Indicator Light Remains ON»(ref-382797-S15098386642011012800000) Absorber control indicator light (Does not come on) Refer to «Absorber Control Indicator Light does not Come ON»(ref-382797-S23588834012011012800000)

DTC CHECK / CLEAR

1. DTC CHECK/CLEAR DTC check Connect Techstream to the DLC3. Turn the engine switch on (IG). Read the DTCs following the prompts on the tester screen. DTC clear Connect Techstream to the DLC3. Turn the engine switch on (IG). Operate Techstream to clear the code. HINT: Refer to Techstream operator's manual for further details. Turn both the engine switch and Techstream switch off.
2. END OF DTC CHECK/CLEAR Turn the engine switch on (IG). Check that the absorber control indicator goes off within approximately 2 seconds.

DATA LIST / ACTIVE TEST

1. DATA LIST HINT: According to the DATA LIST displayed on Techstream, the value and status of the switch, sensor, actuator, etc. can be obtained without part removal. Reading the DATA LIST as the first step in troubleshooting is one way to shorten labor time. Connect Techstream to the DLC3. Turn the engine switch on (IG). From the display on the tester, read the "DATA LIST". Tester Display Measurement Item/Range Normal Condition Diagnostic Note Vehicle Speed Vehicle speed reading/ min.: 0 km/h (0 mph), max.: 255 km/h (158 mph) Actual vehicle speed Speed indicated on speedometer IG Power Source Voltage ECU power supply voltage/ min.: 0 V, max.: 25.5 V Actual ECU power supply voltage: 10 to 14 V - Steering Angle Steering angle sensor reading/min.: -73725.75 deg, max.: 73728 deg Actual steering angle Left turn: Reading increases Right turn: Reading decreases Zero point is set when the battery is connected Engine Speed Cam position sensor reading/ min.: 0 rpm, max.: 25,500 rpm Actual engine speed Speed indicated on the combination meter Stop Light Switch Stop light switch/ ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - Damping Force Switch 1 Damping force switch 1/ ON or OFF The same as absorber control switch position Operate the absorber control switch TS Terminal TS terminal/ ON or OFF ON: During test mode OFF: Normal mode - TC Terminal TC terminal/ ON or OFF ON: DTC recorded OFF: No DTC recorded - G (Up & Down) Sensor FR G (up & down) FR sensor reading/ min.: -1045267.3 mm/s 2 , max.: 1045299.2 mm/s 2 -8820 mm/s 2 to 980 mm/s 2 at still condition Reading changes when vehicle (FR) is bounced G (Up & Down) Sensor FL G (up & down) FL sensor reading/ min.: -1045267.3 mm/s 2 , max.: 1045299.2 mm/s 2 -8820 mm/s 2 to 980 mm/s 2 at still condition Reading changes when vehicle (FL) is bounced G (Up & Down) Sensor Rear G (up & down) rear sensor reading/ min.: -1045267.3 mm/s 2 , max.: 1045299.2 mm/s 2 -8820 mm/s 2 to 980 mm/s 2 at still condition Reading changes when vehicle (rear) is bounced Damper Step FR Damper step FR/ min.: 0 step, max.: 255 step Min.: 1 step, max.: 17 step - Damper Step FL Damper step FL/ min.: 0 step, max.: 255 step Min.: 1 step, max.: 17 step - Damper Step RR Damper step RR/ min.: 0 step, max.: 255 step Min.: 1 step, max.: 17 step - Damper Step RL Damper step RL/ min.: 0 step, max.: 255 step Min.: 1 step, max.: 17 step - Wheel Speed FR Front right wheel speed reading/ min.: 0 km/h (0 mph), max.: 255 km/h (158 mph) Actual vehicle speed Speed indicated on speedometer Max Damper Step FR Max. damper step FR/ min.: 0 step, max.: 255 step 17 step at still condition - Max Damper Step FL Max. damper step FL/ min.: 0 step, max.: 255 step 17 step at still condition - Max Damper Step RR Max. damper step RR/ min.: 0 step, max.: 255 step 17 step at still condition - Max Damper Step RL Max. damper step RL/ min.: 0 step, max.: 255 step 17 step at still condition - Number of Trouble Code Number of DTC recorded/ min.: 0, max.: 255 Min.: 0, Max.: XX
2. ACTIVE TEST HINT: Performing the ACTIVE TEST using Techstream allows the relay, actuator, etc. to operate without parts removal. Performing the ACTIVE TEST as the first step of troubleshooting is one way to shorten labor time. It is possible to display the DATA LIST during the ACTIVE TEST. Connect Techstream to DLC3. Turn the engine switch on (IG). According to the display on the tester, perform the "ACTIVE TEST". Tester Display Test Part Control Range Damper Step FR Damper step front right wheel 1 step to 17 steps (Damper step is change) Damper Step FL Damper step front left wheel 1 step to 17 steps (Damper step is change) Damper Step RR Damper step rear right wheel 1 step to 17 steps (Damper step is change) Damper Step RL Damper step rear left wheel 1 step to 17 steps (Damper step is change)

DIAGNOSTIC TROUBLE CODE CHART

HINT

1. If a trouble code is displayed during the DTC check, check the circuit indicated by the DTC. For details of each code,refer to the respective DTC No. in the DTC chart.
2. Inspect the fuse and relay before investigating the trouble areas as shown in the table below.

ADAPTIVE VARIABLE SUSPENSION SYSTEM