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Home >> Honda >> 2021 >> Ridgeline RTL, AWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC System - Diagnostics (B1245 - U129B) >> DTC Troubleshooting >> DTC B2986 (L and WINDSHIELD DEFROST) (Climate Control Unit) (2017 2018 2019 2020)

DTC B2986 (L and WINDSHIELD DEFROST) (Climate Control Unit) (2017 2018 2019 2020)

DTC B2986 or DTC indicator L and WINDSHIELD DEFROST  : An open in the recirculation control motor circuit

DTC Description DTC
B2986 An open in the recirculation control motor circuit  

DTCs (AC)

  1. Problem verification

    -1. Clear the DTCs with the HDS.

    -2. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.

    -3. Do the Self-Diagnostic Function with the HDS or the climate control unit .

    -4. Wait for at least 8 seconds.

    -5. Check for DTCs.

    DTC Description DTC
    B2986 An open in the recirculation control motor circuit  

    Is DTC B2986 or L and WINDSHIELD DEFROST indicated?

    YES 

    Go to step 2.

    NO 

    Intermittent failure. Check for loose wires or poor connections on the recirculation control motor circuit.

  2. Determine possible failure area (FRS REC MODE/FRS REC-P line, others)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Recirculation control motor 7P connector

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    Recirculation control motor 7P connector: disconnected
    Test point 1 Recirculation control motor 7P connector (female terminals) No. 2:
    Test point 2 Body ground
    GHH457167Courtesy of HONDA, U.S.A., INC.

    Is there about 5 V?

    YES 

    The FRS REC MODE/FRS REC-P wire is OK. Go to step 3.

    NO 

    Go to step  4.

  3. Open wire check (SENSOR(COM) line)

    -1. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    Recirculation control motor 7P connector: disconnected
    Test point 1 Recirculation control motor 7P connector (female terminals) No. 2:
    Test point 2 Recirculation control motor 7P connector (female terminals) No. 3:
    GHH457170Courtesy of HONDA, U.S.A., INC.

    Is there about 5 V?

    YES 

    The SENSOR(COM) wire is OK. Replace the recirculation control motor .

    NO 

    Repair an open in the wire between the climate control unit and the recirculation control motor.

  4. Open wire check (FRS REC MODE/FRS REC-P line)

    -1. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    Recirculation control motor 7P connector: disconnected
    Test point 1 Climate control unit connector C (12P) No. 5
    Test point 2 Body ground

    Is there about 5 V?

    YES 

    Repair an open in the wire between the climate control unit and the recirculation control motor.

    NO 

    The FRS REC MODE/FRS REC-P wire is OK. Replace the climate control unit .