Pre-Crash Safety System Power Source Circuit

Restraints. Lexus Gs430, Gs300. Uzs190 Grs190
Pre-Crash Safety. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK WIRE HARNESS (POWER SOURCE CIRCUIT)

CHECK WIRE HARNESS (GROUND CIRCUIT)

PRE-CRASH SAFETY SYSTEM - Power Source Circuit


DESCRIPTION

This circuit supplies power to the seat belt control ECU.
When the engine switch is turned on (IG), the D-IG1 relay turns on and power is supplied to the driver side junction block ECU. Power is then supplied from the driver side junction block ECU to the luggage room junction block ECU, which then turns on the L-IG1 relay to supply power to the seat belt control ECU.
HINT:
There may be a malfunction in the power source circuit if either: 1) neither DTCs nor normal system codes are output but the pre-crash safety system is not functioning normally; or 2) DTCs are not output and a normal system code is output, but the pre-crash safety system is not functioning normally.

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Pre-Crash Safety.Pre-Crash Safety System.Pre-Crash Safety System Power Source Circuit


INSPECTION PROCEDURE

NOTICE:
When the seat belt control ECU is replaced with a new one, Active Test must be performed (Click here).
1.CHECK WIRE HARNESS (POWER SOURCE CIRCUIT)


    Lexus Gs430, Gs300. Uzs190 Grs190.Pre-Crash Safety.Pre-Crash Safety System.Pre-Crash Safety System Power Source Circuit

  1. Disconnect the cable from the negative (-) battery terminal.

  1. Disconnect the connector from the seat belt control ECU.

  1. Connect the cable to the negative (-) battery terminal.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    W30-3 (IG1) - Body ground
    		Engine switch on (IG)
    		10 to 14 V
    W30-9 (+B) - Body ground
    		Always
    		10 to 14 V


NG
REPAIR OR REPLACE WIRE HARNESS (BATTERY-SEAT BELT CONTROL ECU), CHARGING SYSTEM AND BATTERY
OK


2.CHECK WIRE HARNESS (GROUND CIRCUIT)


    Lexus Gs430, Gs300. Uzs190 Grs190.Pre-Crash Safety.Pre-Crash Safety System.Pre-Crash Safety System Power Source Circuit

  1. Disconnect the cable from the negative (-) battery terminal.

  1. Disconnect the connector from the seat belt control ECU.

  1. Measure the resistance of the wire harness side connector.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    W30-18 (PGND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE SEAT BELT CONTROL ECU