Dtc B1579 Voice Recognition Microphone Disconnected
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
CHECK HARNESS AND CONNECTOR (MULTI-MEDIA MODULE RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY)
CHECK MULTI-MEDIA MODULE RECEIVER ASSEMBLY
CHECK MAP LIGHT ASSEMBLY
CHECK MAP LIGHT ASSEMBLY
CHECK TELEPHONE MICROPHONE ASSEMBLY
DTC B1579 Voice Recognition Microphone Disconnected
DESCRIPTION
The multi-media module receiver assembly and map light assembly (telephone microphone assembly) are connected to each other using the microphone connection detection signal lines.
This DTC is stored when a microphone connection detection signal line is disconnected.
DTC Code | DTC Detection Condition | Trouble Area |
B1579 | Telephone microphone signal is lost. | Multi-media module receiver assembly
Map light assembly
Telephone microphone assembly
Harness or connector
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WIRING DIAGRAM

INSPECTION PROCEDURE
1.CHECK HARNESS AND CONNECTOR (MULTI-MEDIA MODULE RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY) |
Disconnect the F77 multi-media module receiver assembly connector.
Disconnect the R7 map light assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection | Condition | Specified Condition |
F77-49 (SNS2) - R7-20 (SNS2) | Always | Below 1 Ω |
F77-29 (MACC) - R7-25 (ACC) | Always | Below 1 Ω |
F77-27 (MIN+) - R7-27 (MI1+) | Always | Below 1 Ω |
F77-48 (MIN-) - R7-26 (MIC-) | Always | Below 1 Ω |
F77-49 (SNS2) - Body ground | Always | 10 kΩ or higher |
F77-29 (MACC) - Body ground | Always | 10 kΩ or higher |
F77-27 (MIN+) - Body ground | Always | 10 kΩ or higher |
F77-48 (MIN-) - Body ground | Always | 10 kΩ or higher |
F77-28 (SGND) - Body ground | Always | 10 kΩ or higher |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
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2.CHECK MULTI-MEDIA MODULE RECEIVER ASSEMBLY |
Reconnect the multi-media module receiver assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection | Condition | Specified Condition |
F77-28 (SGND) - Body ground | Always | Below 1 Ω |
F77-48 (MIN-) - Body ground | Always | Below 1 Ω |
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection | Switch Condition | Specified Condition |
F77-29 (MACC) - Body ground | Engine switch on (ACC) | 4 to 6 V |
Text in Illustration*a | Component with harness connected (Multi-media Module Receiver Assembly) |
| REPLACE MULTI-MEDIA MODULE RECEIVER ASSEMBLY ()
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3.CHECK MAP LIGHT ASSEMBLY |
Remove the map light assembly ().
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection | Condition | Specified Condition |
26 (MIC-) - 20 (SNS2) | Always | Below 1 Ω |
Text in Illustration*a | Component without harness connected (Map Light Assembly) |
4.CHECK MAP LIGHT ASSEMBLY |
Reconnect the multi-media module receiver assembly connector.
Reconnect the map light assembly connector.
Turn the engine switch on (ACC).
Connect an oscilloscope to terminals R7-27 (MI1+) and R7-26 (MIC-) of the map light assembly connector.
Check the waveform of the telephone microphone assembly using the oscilloscope.
Text in Illustration*a | Component with harness connected (Map Light Assembly) |
ResultResult | Proceed to |
A waveform synchronized with the voice input to the map light assembly is not output. | A |
A waveform synchronized with the voice input to the map light assembly is output. | B |
| REPLACE MULTI-MEDIA MODULE RECEIVER ASSEMBLY ()
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5.CHECK TELEPHONE MICROPHONE ASSEMBLY |
Replace the telephone microphone assembly with a new or normally functioning one ().
Check if the same DTC is output again.
ResultResult | Proceed to |
No DTCs are output. | A |
DTCs are output. | B |
| REPLACE MAP LIGHT ASSEMBLY ()
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A | |
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END (TELEPHONE MICROPHONE ASSEMBLY IS DEFECTIVE) |
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