Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

CHECK WIRE HARNESS (AFS ECU - BATTERY AND BODY GROUND)

Disconnect the A31 ECU connector.

Measure the voltage of the wire harness side connector.

Standard voltage

VOLTAGE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
A31-2 (IG) - Body ground	Ignition switch ON	10 to 14 V
A31-2 (IG) - Body ground	Ignition switch OFF	Below 1 V

Measure the resistance of the wire harness side connector.

Fig 1: Identifying AFS ECU Connector Terminals

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
A31-1 (E1) - Body ground	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

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