Inspection Procedure

1. Check that the steering pad switch can operate the audio system normally.

   OK: Steering pad switch can operate the audio system normally. 

OK: REPLACE STEERING PAD SWITCH MODULATOR 

NG: Go to next step. 

1. Disconnect the C10 modulator connector.
2. Disconnect the D4 ECU connector.
   Fig 1: Identifying C10 Modulator Connector And D4 ECU Connector

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

   Standard resistance 

   RESISTANCE SPECIFICATION
   
   

   Tester Connection	Specified Condition
   C10-3 (MPX) - D4-6 (MPX3)	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step. 

1. Remove the PANEL and SECURITY fuses from driver side junction block.
2. Measure the resistance of the fuses.

   OK: Below 1 Ω 

NG: REPLACE FUSE 

OK: Go to next step. 

1. Disconnect the C10 modulator connector.
   Fig 2: Identifying C10 Modulator Connector

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

   Standard voltage 

   VOLTAGE SPECIFICATION
   
   

   Tester Connection	Specified Condition
   C10-2 (+B) - Body ground	10 to 14 V

   Standard resistance 

   RESISTANCE SPECIFICATION
   
   

   Tester Connection	Specified Condition
   C10-4 (ECC) - Body ground	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: REPLACE STEERING PAD SWITCH MODULATOR