Seat Belt Control ECU Communication Stop Mode: Procedure

WARNING: This page is about a different car, the 2009 Lexus IS 350 and 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

CHECK OPEN IN CAN BUS WIRE (SEAT BELT CONTROL ECU BRANCH LINE)

Turn the engine switch off.
Disconnect the seat belt control ECU connectors.

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

Fig 1: Identifying Seat Belt Control ECU Branch Line

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Standard Resistance

Tester Connection	Switch Condition	Specified Condition
Q59-1 (CANH) - Q58-2 (CANL)	Engine switch off	54 to 69 Ω

NG → REPAIR OR REPLACE SEAT BELT CONTROL ECU BRANCH WIRE OR CONNECTOR (CAN-H, CAN-L)

OK: Go to next step

CHECK WIRE HARNESS (IG1, PGND)

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

Fig 2: Identifying Wire Harness (IG1, PGND)

Standard Resistance

Tester Connection	Condition	Specified Condition
Q58-8 (PGND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
Q59-8 (IG1) - Body ground	Engine switch on (IG)	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK → REPLACE SEAT BELT CONTROL ECU