Inspection Procedure

WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

Disconnect the negative (-) terminal cable from the battery.
Disconnect the O38 seat belt control ECU connector.
Connect the negative (-) terminal cable to the battery.

Measure the voltage according to the value (s) in POWER SOURCE CIRCUIT .

Standard voltage

POWER SOURCE CIRCUIT

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

Fig 1: Disconnecting O38 Seat Belt Control ECU Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

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

Measure the resistance according to the value (s) in GROUND CIRCUIT .

Standard resistance

GROUND CIRCUIT

Tester Connection	Condition	Specified Condition
O38-18 (PGND) - Body ground	Always	Below 1 ohms

Fig 2: Identifying Harness & Connector (Ground Circuit)

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SEAT BELT CONTROL ECU