LEMON Manuals: Even more car manuals for everyone
Home >> Honda >> 2021 >> CR-V EX-L, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 82 (Real Time AWD Control Unit - Diagnostics (Hybrid)) >> Troubleshooting >> DTC C1851-19, C1851-1E

DTC C1851-19, C1851-1E

WARNING: This page is about a different variant/trim than selected.

DTC C1851-19  : Control Module Internal Control Module Malfunction

DTC C1851-1E  : Motor Circuit High Current

NOTE:  Before you troubleshoot, review the General Troubleshooting Information .

DTC Description DTC Freeze Frame
C1851-19 Control Module Internal Control Module Malfunction    
C1851-1E Motor Circuit High Current    

DTC (Real Time AWD)

  1. Problem verification (with engine idling)

    -1. Turn the vehicle to the ON mode.

    -2. Clear the DTC with the HDS.

    -3. Turn the vehicle to the OFF (LOCK) mode.

    -4. Enter the maintenance mode and start the engine .

    -5. Check for DTCs with the HDS.

    DTC Description DTC Freeze Frame
    C1851-19 Control Module Internal Control Module Malfunction    
    C1851-1E Motor Circuit High Current    

    Is DTC C1851-19 or C1851-1E indicated?

    YES 

    The failure is duplicated. Go to step 3.

    NO 

    Go to step 2.

  2. Problem verification (with rear differential pump motor running)

    -1. Clear the DTC with the HDS.

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

    -3. Enter the maintenance mode and start the engine .

    -4. Select the ADJUSTMENT in the REAL TIME AWD with the HDS.

    -5. With the engine running, do the AIR BLEEDING in the ADJUSTMENT with the HDS .

    Air Bleeding

    Check for DTCs with the HDS.

    DTC Description DTC Freeze Frame
    C1851-19 Control Module Internal Control Module Malfunction    
    DTC Description DTC Freeze Frame
    C1851-1E Motor Circuit High Current    

    Is DTC C1851-19 or C1851-1E indicated?

    YES 

    The failure is duplicated. Go to step 3.

    NO 

    Intermittent failure, the system is OK at this time. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

  3. Determine possible failure area (short to power in MH, ML lines, others)

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

    -2. Disconnect the following connector.

    Rear differential pump motor 2P connector

    -3. Turn the vehicle to the ON mode.

    -4. Wait for 10 seconds.

    -5. Measure the voltage between the following test points 1 and 2 individually.

    Test condition Vehicle ON mode
      Rear differential pump motor 2P connector: disconnected
    Connector Test point 1 Test point 2
    Rear differential pump motor 2P connector (female terminals) No. 1: Body ground
    No. 2:
    GHH380529Courtesy of HONDA, U.S.A., INC.

    Is there about 0.1 V or less?

    YES 

    Go to step 5.

    NO 

    Go to step 4.

  4. Shorted wire check (MH line to power, ML line to power)

    -1. Disconnect the following connector.

    AWD control unit 24P connector

    -2. Turn the vehicle to the ON mode.

    -3. Measure the voltage between the following test points 1 and 2 individually.

    Test condition Vehicle ON mode
      Rear differential pump motor 2P connector: disconnected
      AWD control unit 24P connector: disconnected
    Connector Test point 1 Test point 2
    Rear differential pump motor 2P connector (female terminals) No. 1: Body ground
    No. 2:
    GHH380532Courtesy of HONDA, U.S.A., INC.

    Is there about 0.1 V or less?

    YES 

    Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit , and recheck. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit .

    NO 

    Repair short to power in the MH and/or ML wires between the rear differential pump motor and the AWD control unit.

  5. Determine possible failure area (short to ground in MH line, others)

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

    -2. Connect the following connector.

    Rear differential pump motor 2P connector

    -3. Disconnect the following connector.

    AWD control unit 24P connector

    -4. Measure the resistance between the following test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    AWD control unit 24P connector: disconnected
    Test point 1 AWD control unit 24P connector No. 1
    Test point 2 Body ground

    Is there 1.0 MΩ or more?

    YES 

    Go to step 7.

    NO 

    Go to step 6.

  6. Rear differential pump motor check

    -1. Disconnect the following connector.

    Rear differential pump motor 2P connector

    -2. On the rear differential pump motor side, measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    Rear differential pump motor 2P connector: disconnected
    Test point 1 Rear differential pump motor 2P connector (male terminals) No. 1:
    Test point 2 Rear differential pump motor 2P connector (male terminals) No. 2:
    GHH380535Courtesy of HONDA, U.S.A., INC.

    Is there about 0.6 Ω or more?

    YES 

    The rear differential pump motor is OK. Go to step 7.

    NO 

    Replace the rear differential pump motor .

  7. Determine possible failure area (short in MH, ML line, others)

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

    Test condition Vehicle OFF (LOCK) mode
      AWD control unit 24P connector: disconnected
    Test point 1 AWD control unit 24P connector No. 1
    Test point 2 AWD control unit 24P connector No. 3

    Is there 1.0 MΩ or more?

    YES 

    Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit , and recheck. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit .

    NO 

    Go to step 8.

  8. Shorted wire check (MH line to ML line)

    -1. Disconnect the following connector.

    Rear differential pump motor 2P connector

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

    Test condition Vehicle OFF (LOCK) mode
      Rear differential pump motor 2P connector: disconnected
      AWD control unit 24P connector: disconnected
    Test point 1 Rear differential pump motor 2P connector (female terminals) No. 1:
    Test point 2 Rear differential pump motor 2P connector (female terminals) No. 2:
    GHH380538Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 MΩ or more?

    YES 

    The MH wire to the ML wire are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit , and recheck. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit .

    NO 

    Repair a short in the MH wire to the ML wire between the rear differential pump motor and the AWD control unit.