DTC 4-3: Overhead Module Microphone Error: Procedure

1. Start the navigation system and check that the voice recognition microphone function operates normally.
   RESULT
   
   

   Result	Proceed to
   Microphone function is normal	A
   Microphone function is malfunctioning (for DVD)	B
   Microphone function is malfunctioning (for HDD)	C

C → See step   6 

B → See step   5 

A: Go to next step 

Fig 1: Identifying R24 ECU And X4 Map Light Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the R24 ECU connector.
2. Disconnect the X4 map light connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   R24-7 (TACC) - X4-22 (ACC)	Always	Below 1 Ω
   R24-7 (TACC) or X4-22 (ACC) - Body ground	Always	10 kΩ or higher

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

OK: Go to next step 

1. Disconnect the X4 map light connector.
   Fig 2: Identifying X4 Map Light Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   X4-1 (GND) - Body ground	Always	Below 1 Ω

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

OK: Go to next step 

1. Temporarily replace the map light with a new or normally functioning one. Refer to REMOVAL .
2. Check if 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)