Microphone Circuit Between Overhead J/B and Multi-Display

NAVIGATION SYSTEM: Microphone Circuit between Overhead J/B and Multi-display

Microphone Circuit between Overhead J/B and Multi-display

DESCRIPTION

w/o LEXUS Link System:
This circuit sends a microphone signal from the microphone to the multi-display. It also supplies power from the multi-display to the microphone.
w/ LEXUS Link System:
This circuit sends a microphone signal from the microphone to the multi-display through the mayday ECU. It also supplies power from the mayday ECU to the microphone.

WIRING DIAGRAM









INSPECTION PROCEDURE

PROCEDURE

1. CHECK MULTI-DISPLAY





(a) Check that waveform of the microphone using an oscilloscope.






OK:
Waveform that matches sound spoken into microphone is output.
OK -- REPLACE MULTI-DISPLAY
NG -- Continue to next step.
2. CHECK LEXUS LINK SYSTEM
(a) Check if the vehicle is equipped with the LEXUS link system.

Result





B -- CHECK HARNESS AND CONNECTOR (MAYDAY ECU - MULTI-DISPLAY AND MICROPHONE)
A -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (OVERHEAD JUNCTION BLOCK - MULTI-DISPLAY)





(a) Disconnect the O2 junction block connector.
(b) Disconnect the M20 display connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK MULTI-DISPLAY (MACC VOLTAGE)





(a) Reconnect the M20 display connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPLACE MULTI-DISPLAY
OK -- Continue to next step.
5. CHECK MICROPHONE ASSEMBLY





(a) Remove the microphone from the overhead junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE MICROPHONE ASSEMBLY
OK -- PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE
6. CHECK HARNESS AND CONNECTOR (MAYDAY ECU - MULTI-DISPLAY AND MICROPHONE)





(a) Disconnect the M15 ECU connector.
(b) Disconnect the M20 display connector.
(c) Disconnect the O2 microphone connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK MAYDAY ECU (TACC VOLTAGE)





(a) Reconnect the M15 ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPLACE MAYDAY ECU
OK -- Continue to next step.
8. CHECK MICROPHONE ASSEMBLY





(a) Remove the microphone from the overhead junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE MICROPHONE ASSEMBLY
OK -- PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE