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DTC B1775: Microphone Input/Output Shorted to Power or Open (Without Navigation) (2018-19)
NOTE:
- Check the vehicle 12 volt battery condition first - Refer to: 12 Volt Battery Test (Without SH-AWD) or 12 Volt Battery Test (With SH-AWD) .
- Before you troubleshoot, make sure to follow the General Troubleshooting Information .
- Check the connectors for poor connections or loose terminals.
- Problem verification
-1. Check for HFL DTCs.
Is DTC B1775 indicated?
YES
The failure is duplicated, go to step 2.
NO
Intermittent failure, the system is OK at this time.
- Shorted wire check (MIC SIG L line to power)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connectors.
HandsFreeLink control unit connector A (32P) Front HFL-ANC/active sound control microphone 8P connector - 3. Turn the vehicle to the ON mode.
- 4. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode HandsFreeLink control unit connector A (32P): disconnected Front HFL-ANC/active sound control microphone 8P connector: disconnected Test point 1 Front HFL-ANC/active sound control microphone 8P connector No. 2 Test point 2 Body ground Is there more than 8.0 V?
YES
There is a short to power in the wire between the HandsFreeLink control unit and the front HFL-ANC/active sound control microphone. Replace the affected shielded harness.
NO
The MIC SIG L wire is not shorted to power. Go to step 3.
- Determine possible failure area (MIC SIG L line, others)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Reconnect HandsFreeLink control unit connector A (32P).
- 3. Turn the vehicle to the ON mode.
- 4. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Front HFL-ANC/active sound control microphone 8P connector: disconnected Test point 1 Front HFL-ANC/active sound control microphone 8P connector No. 2 Test point 2 Body ground Is there about 8.0 V?
YES
Go to step 5.
NO
Go to step 4.
- Open wire check (MIC SIG L line)
-1. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Front HFL-ANC/active sound control microphone 8P connector: disconnected Test point 1 HandsFreeLink control unit connector A (32P) No. 2 - Refer to: HandsFreeLink Control Unit Connector For Inputs And Outputs (2015-17) or HandsFreeLink Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Body ground Is there about 8.0 V?
YES
There is an open in the wire between the HandsFreeLink control unit and the front HFL-ANC/active sound control microphone. Replace the affected shielded harness.
NO
- Open wire check (MIC GND line)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
HandsFreeLink control unit connector A (32P) - 3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Front HFL-ANC/active sound control microphone 8P connector: disconnected HandsFreeLink control unit connector A (32P): disconnected Test point 1 HandsFreeLink control unit connector A (32P) No. 1 - Refer to: HandsFreeLink Control Unit Connector For Inputs And Outputs (2015-17) or HandsFreeLink Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Front HFL-ANC/active sound control microphone 8P connector No. 1 Is there continuity?
YES
The MIC GND wire is OK. Go to step 6.
NO
There is an open in the wire between the HandsFreeLink control unit and the front HFL-ANC/active sound control microphone. Replace the affected shielded harness.
- Shorted wire check (NAVI HFT MIC+ line to power)
-1. Disconnect the following connector.
Audio unit connector F (18P) - 2. Turn the vehicle to the ON mode.
- 3. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode HandsFreeLink control unit connector A (32P): disconnected Audio unit connector F (18P): disconnected Test point 1 Audio unit connector F (18P) No. 13 - Refer to: Audio Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or Audio Unit Connector For Inputs And Outputs (Without Auto Idle Stop System) (2015-17) or Audio Unit Connector for Inputs and Outputs (Undefined) (2018), or Audio Unit Connector for Inputs and Outputs (2019) Test point 2 Body ground Is there about 8.0 V or more?
YES
There is a short to power in the wire between the HandsFreeLink control unit and the audio unit. Replace the affected shielded harness.
NO
The NAVI HFT MIC+ wire is not shorted to power. Go to step 7.
- Determine possible failure area (audio unit, others)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Reconnect HandsFreeLink control unit connector A (32P).
- 3. Reconnect the front HFL-ANC/active sound control microphone 8P connector.
- 4. Check for HFL DTCs.
Is DTC B1775 indicated?
YES
Go to step 8.
NO
- Front HFL-ANC/active sound control microphone check
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Substitute a known-good front HFL-ANC/active sound control microphone.
- 3. Check for HFL DTCs.
Is DTC B1775 indicated?
YES
Replace the HandsFreeLink control unit .
NO
Replace the original front HFL-ANC/active sound control microphone .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.