DTC 4-3: Overhead Module Microphone Error: Procedure

1. Start the navigation system and check that the voice recognition microphone function operates normally.
   1. If the microphone function is normal, proceed to A.
   2. If the microphone function is malfunctioning, proceed to B.

B → See step   5 

A: Go to next step 

1. Disconnect the M15 ECU connector.
   Fig 1: Identifying Roof Console Box & Mayday ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the O2 roof console box connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   M15-7 (TACC) - O2-9 (MACC)	Below 1 Ω
   M15-7 (TACC) or O2-9 (MACC) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the O2 roof console box connector.
   Fig 2: Identifying Roof Console Box Connector Terminals

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

   Standard resistance

   Tester Connection	Specified Condition
   O2-4 (GND) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Temporarily replace the roof console box assembly. Refer to REMOVAL with a new or normally functioning one.
2. Check that the DTC 4-3 is output.

   OK

   DTC 4-3 is not output.

   NOTE:

   If replacement of the ECU is necessary, replace the mayday battery (backup battery) together with the ECU. After the replacement, register the ECU. Refer to REGISTRATION .

NG → See step   6 

OK → END