DTC Troubleshooting: B1776
DTC B1776: Microphone Input/Output Shorted to Ground
NOTE:
1.
Problem verification:

Problem verification
?1.
Check for HFL DTCs.

Is DTC B1776 indicated?

     
YES
     
     
     
The failure is duplicated, go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time.?
2.
Shorted wire check (MIC+L line):

Shorted wire check (MIC+L line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connectors.

?3.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
 
HandsFreeLink control unit connector A (32P): disconnected
 
Front HFL-navigation-ANC/active sound control microphone 8P connector: disconnected
Test circuit
MIC+L
Test point 1
HandsFreeLink control unit connector A (32P) No. 2 (LT GRN)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
There is a short to body ground in the wire between the HandsFreeLink control unit and the front HFL-navigation-ANC/active sound control microphone. Replace the affected shielded harness.?
     
NO
     
     
     
The MIC+L wire is not shorted to ground. Go to step 3.
3.
Shorted wire check (MIC+L line to another lines):

Shorted wire check (MIC+L line to another lines)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
 
HandsFreeLink control unit connector A (32P): disconnected
 
Front HFL-navigation-ANC/active sound control microphone 8P connector: disconnected
Test circuit
MIC+L, MIC+
Test point 1
HandsFreeLink control unit connector A (32P) No. 2 (LT GRN)
Test point 2
HandsFreeLink control unit connector A (32P) No. 1 (PNK)

Test circuit
MIC+L, SH MIC
Test point 1
HandsFreeLink control unit connector A (32P) No. 2 (LT GRN)
Test point 2
HandsFreeLink control unit connector A (32P) No. 3 (BLK)


Is there continuity?

     
YES
     
     
     
There is a short in the wires between the HandsFreeLink control unit and the front HFL-navigation-ANC/active sound control microphone. Replace the affected shielded harness.?
     
NO: With navigation
     
     
     
The MIC+L wire is OK. Go to step 5.
     
NO: Without navigation
     
     
     
The MIC+L wire is OK. Go to step 4.
4.
Front HFL-ANC/active sound control microphone check (substitution):

Front HFL-ANC/active sound control microphone check (substitution)
?1.
Substitute a known-good front HFL-ANC/active sound control microphone.

?2.
Reconnect all the connectors.

?3.
Check for HFL DTCs.

Is DTC B1776 indicated?

     
YES
     
     
     
     
NO
     
     
     
Replace the original front HFL-ANC/active sound control microphone.?
5.
Shorted wire check (HFT-NAVI MIC+ line):

Shorted wire check (HFT-NAVI MIC+ line)
?1.
Disconnect the following connector.

?2.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
HandsFreeLink control unit connector A (32P) : disconnected
 
Front HFL-navigation-ANC/active sound control microphone 8P connector: disconnected
 
Audio-navigation unit connector F (18P): disconnected
Test circuit
HFT-NAVI MIC+
Test point 1
Audio-navigation unit connector F (18P) No. 13 (GRN)
Test point 2
Body ground


Is there any voltage?

     
YES
     
     
     
There is a short to body ground in the wire between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.?
     
NO
     
     
     
The HFT-NAVI MIC+ wire is not shorted to ground. Go to step 6.
6.
Shorted wire check (HFT-NAVI MIC+ line to another lines):

Shorted wire check (HFT-NAVI MIC+ line to another lines)
?1.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
HandsFreeLink control unit connector A (32P): disconnected
 
Front HFL-navigation-ANC/active sound control microphone 8P connector: disconnected
 
Audio-navigation unit connector F (18P): disconnected
Test circuit
HFT-NAVI MIC+, HFT-NAVI MIC?
Test point 1
Audio-navigation unit connector F (18P) No. 13 (GRN)
Test point 2
Audio-navigation unit connector F (18P) No. 14 (RED)

Test circuit
HFT-NAVI MIC+, SH HFT-NAVI MIC
Test point 1
Audio-navigation unit connector F (18P) No. 13 (GRN)
Test point 2
Audio-navigation unit connector F (18P) No. 6 (GRY)


Is there continuity?

     
YES
     
     
     
There is a short in the wires between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.?
     
NO
     
     
     
The HFT-NAVI MIC+ wire is OK. Go to step 7.
7.
Determine possible failure area (audio-navigation unit, others):

Determine possible failure area (audio-navigation unit, others)
?1.
Reconnect the HandsFreeLink control unit connector A (32P) and the front HFL-navigation-ANC/active sound control microphone 8P connector.

?2.
Check for HFL DTCs.

Is DTC B1776 indicated?

     
YES
     
     
     
Go to step 8.
     
NO
     
     
     
8.
Front HFL-navigation-ANC/active sound control microphone check (substitution):

Front HFL-navigation-ANC/active sound control microphone check (substitution)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Substitute a known-good front HFL-navigation-ANC/active sound control microphone.

?3.
Check for HFL DTCs.

Is DTC B1776 indicated?

     
YES
     
     
     
     
NO
     
     
     
Replace the original front HFL-navigation-ANC/active sound control microphone.?