Inspection Procedure

1. Remove the RADIO NO. 1 fuse from the engine room No. 1 relay block.
2. Remove the RADIO NO. 2 fuse from the passenger side junction block.
3. Remove the AM1 fuse from the driver side junction block.
4. Measure the resistance of the fuses.

   Standard resistance: 

   Below 1 Ω 

NG: REPLACE FUSE 

OK: Go to next step 

1. Disconnect the S22 and S23 amplifier connectors.
   Fig 1: Identifying S22 And S23 Amplifier Connectors Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance and voltage of the wire harness side connectors.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Specified Condition
   S22-13 (GND) - Body ground	Below 1 Ω
   S22-12 (E) - Body ground	Below 1 Ω

   Standard voltage 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Condition	Specified Condition
   S22-7 (+B) - Body ground	Always	10 to 14 V
   S22-16 (+B) - Body ground	Always	10 to 14 V
   S23-20 (ACC) - Body ground	Ignition switch ACC	10 to 14 V

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

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