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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 (5) (HVAC Control Unit)

DTC B2986 (5) (HVAC Control Unit)

DTC B2986 or DTC indicator 5  : 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 HVAC 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 5 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
    GHH457162Courtesy 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:
    GHH457165Courtesy 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 HVAC 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 HVAC 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 HVAC control unit and the recirculation control motor.

    NO 

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