Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (MULTI-DISPLAY - MAIN BODY ECU)

Disconnect the M21 display connector.
Disconnect the B5 ECU connector.

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

Standard resistance

MULTI-DISPLAY - MAIN BODY ECU

Tester Connection	Condition	Specified Condition
M21-17 (DR) - B5-5 (ACAN)	Always	Below 1 Ω
M21-17 (DR) - Body ground	Always	10 kΩ or higher

Fig 1: Identifying Harness & Connector (Multi-Display - Main Body ECU)

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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

CHECK MAIN BODY ECU (ACAN VOLTAGE)

Reconnect the B5 ECU connector.
Turn the ignition switch ON.
Turn the light control switch to the TAIL or HEAD position.

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

Standard voltage

MAIN BODY ECU (ACAN VOLTAGE)

Tester connection	Condition	Specified condition
B5-5 (ACAN) - Body ground	Automatic light control sensor is covered.	Above 9 V

Fig 2: Identifying Main Body ECU (ACAN Voltage)

NG: GO TO LIGHTING SYSTEM

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE