Pre-Collision System (Diagnostics - Introduction): Diagnosis Lexus GS III facelift

HOW TO PROCEED WITH TROUBLESHOOTING

HINT

1. Use these procedures to troubleshoot the pre-collision system.
2. *:Use the Techstream.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CHECK MULTIPLEX COMMUNICATION SYSTEM Check for DTCs. DTC is not output A DTC is output B B --> GO TO MULTIPLEX COMMUNICATION SYSTEM A: Go to next step
3. CHECK CAN COMMUNICATION SYSTEM* Check for DTCs. DTC is not output A DTC is output B B --> GO TO CAN COMMUNICATION SYSTEM A: Go to next step
4. CHECK FOR DTC* Check for DTCs. Record the DTCs. Clear the DTCs. Recheck for DTCs. Simulate the malfunction and check if the DTCs are output again. Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-382818-S03195636352011012800000) . DTC is output A No DTC is output B No DTC is output, and malfunction can't be simulated or checked C B --> GO TO STEP 9 C --> SYMPTOM SIMULATION A: Go to next step
5. DTC CHART* NEXT: Go to next step
6. CIRCUIT INSPECTION NEXT: Go to next step
7. REPAIR* NEXT: Go to next step
8. CONFIRMATION TEST NEXT --> END
9. PROBLEM SYMPTOMS TABLE NEXT: Go to next step
10. ADJUST, REPAIR OR REPLACE NEXT: Go to next step
11. CONFIRMATION TEST NEXT --> END

PROBLEM SYMPTOMS TABLE

Pre-collision system

Scheme 3

1. CHECK SEAT BELT CONTROL ECU Terminal No. (Symbols) Wiring Color Terminal Description Condition Specified Value V31-2 (MOR+) - V31-8 (PGND) B - W-B Seat belt motor RH power source line Engine switch on (IG) 4.0 to 8.5 V V31-3 (MOL+) - V31-8 (PGND) GR - W-B Seat belt motor LH power source line Engine switch on (IG) 4.0 to 8.5 V V43-8 (IG1) - Body ground G - Body ground Seat belt control ECU power source line Engine switch on (IG) 10 to 14 V V43-1 (CANH) - Body ground B CAN communication Engine idling Pulse generation V43-2 (CANL) - Body ground W CAN communication Engine idling Pulse generation V31-7 (+B) - Body ground L - Body ground Seat belt control ECU power source line Always 10 to 14 V V31-1 (MOR-) - Body ground LG - Body ground Seat belt motor RH ground line Engine switch on (IG) 4.0 to 8.5 V V31-4 (MOL-) - Body ground BR - Body ground Seat belt motor LH ground line Engine switch on (IG) 4.0 to 8.5 V V31-8 (PGND) - Body ground W-B - Body ground Seat belt control ECU ground line Always Below 1 ohms

Scheme 4

Scheme 5

1. CHECK DLC3 The seat belt control ECU uses CAN and ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format. Symbols (Terminals No.) Terminal Description Condition Specified Condition SIL (7) - SG (5) Bus "+" line During transmission 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 10 to 14 V CANH (6) - CANL (14) HIGH - level CAN bus line Engine switch off 54 to 69 ohms CANH (6) - CG (4) HIGH - level CAN bus line Engine switch off 200 ohms or higher CANL (14) - CG (4) LOW - level CAN bus line Engine switch off 200 ohms or higher CANH (6) - BAT (16) HIGH - level CAN bus line Engine switch off 6k ohms or higher CANL (14) - BAT (16) LOW - level CAN bus line Engine switch off 6k ohms or higher If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector. HINT: Connect the cable of the Techstream to the DLC3, turn the engine switch on (IG) and attempt to use the Techstream. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the Techstream. If communication is normal when the Techstream is connected to another vehicle, inspect the DLC3 of the original vehicle. If communication is still not possible when the Techstream is connected to another vehicle, the problem may be in the Techstream itself. Consult the Service Department listed in the Techstream's instruction manual.
2. FUNCTION OF WARNING INDICATOR AND MESSAGE If the pre-collision system is not functioning properly, the driver is warned through the combination meter's master warning indicator and multi-information display warning message. Initial check. The initial check occurs when the engine switch is off for more than 2 seconds, and then the turned on (IG). The initial check consists of a pre-collision system diagnostic check with a duration of approximately 3 seconds. If a malfunction is detected during the initial check, the multi-information display will output "CHECK PCS SYSTEM" or "PCS NOT DISABLE NOW". Constant check. The seat belt control ECU and cruise control ECU assembly (distance control ECU) constantly monitor the pre-collision system for malfunctions after the initial check (approximately 3 seconds after turning the engine switch on (IG). "CHECK PCS SYSTEM" or "PCS NOT DISABLE NOW" is displayed on the multi-information display in the combination meter assembly when the constant check detects malfunctions in the pre-collision system. Review. Master Warning Indicator Warning Message Detail DTC PCS Warning indicator ON CHECK PCS SYSTEM This message appears when the seat belt control ECU detects a system malfunction o ON Illuminate PCS NOT DISABLE NOW This message appears when the seat belt control ECU is in the fail-safe mode. Refer to «FAIL-SAFE CHART»(ref-382818-S07969288352011012800000) - Blinking

DTC CHECK / CLEAR

1. CHECK DTC Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Pre-Collision / Trouble Codes. Check the details of the DTC(s). Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-382818-S03195636352011012800000) .
2. CLEAR DTC Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Pre-Collision / Trouble Codes. Clear the DTCs.

DATA LIST / ACTIVE TEST

1. READ DATA LIST HINT: Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Pre-Collision / Data List. Read the Data List according to the display on the Techstream. Pre-Collision: Tester Display Measurement Item/Range Normal Condition Diagnostic Note Driver Buckle SW Buckle switch status of driver's seat / UNSET / SET /NG UNSET: Unfasten driver side seat belt SET: Fasten driver side seat belt NG: Indeterminate data - Passenger Buckle SW Buckle switch status of passenger's seat / UNSET / SET /NG UNSET: Unfasten passenger side seat belt SET: Fasten passenger side seat belt NG: Indeterminate data - Drive Belt Control Seat belt control status of driver's seat / STOP / ON / ERROR STOP: Control stopped ON: Controlled ERROR: Indeterminate data Seat belt (driver side) is fastened Passenger Belt Control Seat belt control status of passenger's seat / STOP / ON / ERROR STOP: Control stopped ON: Controlled ERROR: Indeterminate data Seat belt (passenger side) is fastened Number of Trouble Codes Number of trouble codes (present and past) / min: 0, max: 255 Number of DTCs will be displayed
2. PERFORM ACTIVE TEST HINT: Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Pre-Collision / Active Test. Perform Active Test according to the display on the Techstream. HINT: The engine switch must be turned on to proceed with the Active Test using the Techstream. Pre-Collision: Tester Display Test Part Control Range Diagnostic Note Driver Seat Belt Motor Driver's seat belt motor ON: Seat belt motor operates OFF: Seat belt motor does not operate Seat belt (driver side) is fastened Passenger Seat Belt Motor Passenger's seat belt motor ON: Seat belt motor operates OFF: Seat belt motor does not operate Seat belt (passenger side) is fastened Drive and Passenger Seat Belt Motor Driver's and passenger's seat belt motor ON: Seat belt motors operate OFF: Seat belt motors do not operate Seat belts (driver and passenger) are fastened NOTE: The belt motor is not equipped with buckle switch is not operated. The protect heating up of belt motor, this test can not be activated continuously. Please operate with 30 seconds interval.

DIAGNOSTIC TROUBLE CODE CHART

Pre-Collision System