Pre-Collision System (Diagnostic Codes): Diagnosis Lexus GS III facelift

INSPECTION PROCEDURE

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Scheme 14

Scheme 15

1. CHECK HARNESS AND CONNECTOR (FRONT SEAT OUTER BELT ASSEMBLY RH - SEAT BELT CONTROL ECU) Disconnect the negative (-) terminal battery. Disconnect the U8 connectors seat belt control ECU and front seat outer belt assembly RH. Connect the negative (-) terminal cable to the battery. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition U8-1 - Body ground Engine switch on (IG) Below 1 V U8-2 - Body ground Engine switch on (IG) Below 1 V Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition U8-1 - U8-2 Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK FRONT SEAT OUTER BELT ASSEMBLY RH Disconnect the U8 connectors seat belt control ECU and front seat outer belt assembly RH. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition U8-1 - Body ground Engine switch on (IG) Below 1 V U8-2 - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FRONT SEAT OUTER BELT ASSEMBLY RH OK --> REPLACE SEAT BELT CONTROL ECU

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Scheme 16

1. CHECK HARNESS AND CONNECTOR (FRONT SEAT OUTER BELT ASSEMBLY RH - SEAT BELT CONTROL ECU) Disconnect the negative (-) terminal battery. Disconnect the connectors seat belt control ECU and front seat outer belt assembly RH. Using a service wire, connect U8-1 and U8-2 of the connector on the front seat outer belt assembly RH side. NOTE: Do not forcibly insert a service wire into the terminals of a connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition V31-2 (MOR+) - V31-1 (MOR-) Always Below 1 Mohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK FRONT SEAT OUTER BELT ASSEMBLY RH Disconnect the connectors seat belt control ECU and front seat outer belt assembly RH. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition U8-1 - U8-2 Always Below 1 Mohms NG --> REPLACE FRONT SEAT OUTER BELT ASSEMBLY RH OK --> REPLACE SEAT BELT CONTROL ECU

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Scheme 17

Scheme 18

1. CHECK HARNESS AND CONNECTOR (FRONT SEAT OUTER BELT ASSEMBLY LH - SEAT BELT CONTROL ECU) Disconnect the negative (-) terminal battery. Disconnect the connectors seat belt control ECU and front seat outer belt assembly LH. Connect the negative (-) terminal cable to the battery. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition V6-1 - Body ground Engine switch on (IG) Below 1 V V6-2 - Body ground Engine switch on (IG) Below 1 V Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition V6-1 - V6-2 Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK FRONT SEAT OUTER BELT ASSEMBLY LH Disconnect the connectors seat belt control ECU and front seat outer belt assembly LH. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition V6-1 - Body ground Engine switch on (IG) Below 1 V V6-2 - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH OK --> REPLACE SEAT BELT CONTROL ECU

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Scheme 19

1. CHECK HARNESS AND CONNECTOR (FRONT SEAT OUTER BELT ASSEMBLY LH - SEAT BELT CONTROL ECU) Disconnect the negative (-) terminal cable battery. Disconnect the connectors seat belt control ECU and front seat outer belt assembly LH. Using a service wire, connect V6-1 and V6-2 of the connector on the front seat outer belt assembly LH side. NOTE: Do not forcibly insert a service wire into the terminals of a connector. Measure the resistance according to the value(s) in the table below. Standard resistance: Tester Connection Condition Specified Condition V31-3 (MOL+) - V31-4 (MOL-) Always Below 1 Mohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK FRONT SEAT OUTER BELT ASSEMBLY LH Disconnect the connectors seat belt control ECU and front seat outer belt assembly LH. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition V6-1 - V6-2 Always Below 1 Mohms NG --> REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH OK --> REPLACE SEAT BELT CONTROL ECU

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. Inspect the fuses for circuits related to this system before performing the following inspection procedure. The pretensioner is built into the front seat outer belt assembly. Be sure to follow the correct inspection procedure, as failure to follow the correct procedure (such as inspection of incorrect connectors) may deploy the pretensioner.

Scheme 20

1. INSPECT SEAT BELT CONTROL ECU (+B TERMINAL VOLTAGE) Disconnect the negative (-) battery terminal. WARNING: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system. Disconnect the V31 connector of the seat belt control ECU. Connect the negative (-) battery terminal. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition V31-7 (+B) - Body ground Engine switch OFF 11 to 14 V Disconnect the negative (-) battery terminal. Reconnect the V31 seat belt control ECU connector. Connect the negative (-) battery terminal. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE SEAT BELT CONTROL ECU

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the distance control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Refer to U0100 (CAN communication system) Refer to PRECAUTION .

Refer to U0122 (CAN communication system) Refer to PRECAUTION .

Refer to U0146 (CAN communication system) Refer to PRECAUTION .

Refer to U1101 (CAN communication system) Refer to PRECAUTION .

Refer to U0235 (Dynamic radar cruise control system) Refer to DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor .

Refer to U1102 (Dynamic radar cruise control system) Refer to DTC U1102: Lost Communication with Radar Sensor .

Note. When the seat belt control ECU is replaced with a new one, Active Test must be performed. Refer to DATA LIST / ACTIVE TEST

Scheme 21

Scheme 22

1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the negative (-) terminal cable from the battery. Disconnect the connectors from the seat belt control ECU. Connect the negative (-) terminal cable to the battery. Measure the voltage according to the value (s) in the table below. Standard voltage Tester Connection Condition Specified Condition V43-8 (IG1) - Body ground Engine switch off Below 1 V Engine switch on (IG) 10 to 14 V V31-7 (+B) - Body ground Always 10 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR ((BATTERY-SEAT BELT CONTROL ECU), CHARGING SYSTEM AND BATTERY) OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Disconnect the negative (-) terminal cable from the battery. Measure the resistance according to the value (s) in the table below. Standard resistance Tester Connection Condition Specified Condition V31-8 (PGND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE SEAT BELT CONTROL ECU