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 → GO TO NAVIGATION SYSTEM 

A: Go to next step 

Fig 1: Identifying U45 ECU Connector And W6 MAP Light Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the U45 ECU connector.
2. Disconnect the W6 map light connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   U45-7 (MCVD) - W6-19 (ACC)	Below 1 Ω
   U45-7 (MCVD) or W6-19 (ACC) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC 

OK: Go to next step 

1. Disconnect the W6 map light connector.
   Fig 2: Identifying W6 MAP Light Connector

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

   Standard resistance

   Tester Connection	Specified Condition
   W6-31 (GND3) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC 

OK: Go to next step 

1. Temporarily replace the map light with a new or normally functioning one.
2. Check that the DTC 4-3 is output.

   OK

   DTC 4-3 is not output.

NG → REPLACE MAYDAY ECU TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION 

OK → END (MAP LIGHT IS FAULTY; CLEAR HISTORIC DTC)