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 (RADIO RECEIVER - STEREO COMPONENT AMPLIFIER)

Disconnect the R3 receiver connector.
Disconnect the S23 amplifier connector.

Fig 1: Identifying S23 Amplifier Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance of the wire harness side connectors.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Specified Condition
R3-7 (MUTE) - S23-21 (MUTE)	Below 1 Ω
R3-7 (MUTE) or S23-21 (MUTE) -Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: Go to next step

CHECK STEREO COMPONENT AMPLIFIER ASSEMBLY (MUTE VOLTAGE)

Fig 2: Identifying Stereo Component Amplifier Assembly Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the voltage of the amplifier.

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
S23-21 (MUTE) - Body ground	Turn ignition switch to ACC. Audio system is playing	Above 3.5 V
S23-21 (MUTE) - Body ground	Turn ignition switch ACC. Audio system mode is Changing	Below 1 V

NG: REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY

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