Microphone Signal Circuit Check

Microphone Signal Circuit Check

Description

Voice signals are transmitted from the microphone to the Bluetooth control unit using the microphone signal circuits.

Diagnosis Procedure

Regarding Wiring Diagram information, refer to [Premium Audio System: Wiring Diagram [Crew Cab] Premium Audio System [Crew Cab] ].

1. CHECK HARNESS BETWEEN BLUETOOTH CONTROL UNIT AND MICROPHONE

1 Turn ignition switch OFF.





2 Disconnect Bluetooth control unit connector B141 and microphone connector R8.
3 Check continuity between Bluetooth control unit harness connector B141 (A) and microphone harness connector R8 (B).






4 Check continuity between Bluetooth control unit harness connector B141 (A) and ground.






Are the continuity test results as specified?
YES
GO TO 2
NO
Repair or replace harness or connector.

2. CHECK MICROPHONE POWER SUPPLY

1 Connect Bluetooth control unit connector B141 and microphone connector R8.





2 Turn ignition switch ON.
3 Check voltage between microphone harness connector R8 terminal 4 and ground.






Is voltage reading approx. 5 volts?
YES
GO TO 3
NO
Replace Bluetooth control unit. Refer to [Bluetooth Control Unit: Removal and Installation] Premium Audio (Crew Cab).

3. CHECK MICROPHONE SIGNAL

Check signal between Bluetooth control unit harness connector B141 terminals 7 and 8 with SDT or and oscilloscope.











Are voltage readings as specified?
YES
Replace Bluetooth control unit. Refer to [Bluetooth Control Unit: Removal and Installation] Premium Audio (Crew Cab).
NO
Replace microphone. Refer to [Microphone: Removal and Installation] Premium Audio (Crew Cab).