Lexus IS250 · Service Manual RESTRAINTS

Power Source Circuit

Circuit diagnosis

DESCRIPTION

This circuit supplies power to the seat belt control ECU.

WIRING DIAGRAM

B124183E01

INSPECTION PROCEDURE

NOTICE:
When the seat belt control ECU is replaced with a new one, INITIALIZATION must be performed (Click here).


1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

  1. G025195E07
    Disconnect the negative (-) terminal cable from the battery.

  1. Disconnect the O38 seat belt control ECU connector.

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

  1. Measure the voltage according to the value (s) in the table below.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    O38-3 (IG1) - Body ground
    		 Engine switch off
    		 Below 1 V
    Engine switch on (IG)
    		 10 to 14 V
    O38-9 (+B) - Body ground
    		 Always
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

  1. G025195E08
    Disconnect the negative (-) terminal cable from the battery.

  1. Measure the resistance according to the value (s) in the table below.

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    O38-18 (PGND) - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE SEAT BELT CONTROL ECU


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