DTC 4-3

CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: 4-3: Overhead Module Microphone Error

DTC 4-3 - Overhead Module Microphone Error

DESCRIPTION

This DTC is output when one of the following occurs: 1) the mayday ECU is malfunctioning; 2) the map light assembly is malfunctioning; 3) the microphone amplifier is malfunctioning; or 4) the wire harness between the mayday ECU and the map light is open or short.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK NAVIGATION SYSTEM
(a) 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 -- Continue to next step.
2. CHECK WIRE HARNESS (MAYDAY ECU - MAP LIGHT)





(a) Disconnect the U45 ECU connector.
(b) Disconnect the W6 map light connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC
OK -- Continue to next step.
3. CHECK WIRE HARNESS (MAP LIGHT - BODY GROUND)





(a) Disconnect the W6 map light connector.
(b) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC
OK -- Continue to next step.
4. CHECK OPERATION OF MAP LIGHT ASSEMBLY
(a) Temporarily replace the map light with a new or normally functioning one.
(b) 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)