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Home >> Acura >> 2014 >> MDX SH-AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System - DTC Diagnostics (3 Of 5) (Except Hybrid) >> DTC Troubleshooting >> DTC P0651 (PGM-FI System (Without Auto Idle Stop System))

DTC P0651 (PGM-FI System (Without Auto Idle Stop System))

DTC P0651  : Sensor Reference Voltage B Malfunction

DTC Description Confirmed DTC Pending DTC Freeze Frame
P0651 Sensor Reference Voltage B Malfunction      

DTC (PGM-FI)

  1. Problem verification

    -1. Turn the vehicle to the ON mode.

    - 2. Clear the DTC with the HDS.

    - 3. Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC Freeze Frame
    P0651 Sensor Reference Voltage B Malfunction      

    Is DTC P0651 indicated?

    YES 

    The failure is duplicated. Go to step 2.

    NO 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the PCM and these parts, 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:?

    • APP sensor
    • Throttle body
    • Rocker arm oil pressure sensor
    • Input shaft (mainshaft) speed sensor
  2. Determine possible failure area (VCC lines, others)

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

    - 2. Disconnect the following connectors.

    APP sensor 6P connector
    Throttle body 6P connector
    Rocker arm oil pressure sensor 3P connector
    Input shaft (mainshaft) speed sensor 3P connector

    - 3. Turn the vehicle to the ON mode.

    - 4. Clear the DTC with the HDS.

    - 5. Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC Freeze Frame
    P0651 Sensor Reference Voltage B Malfunction      

    Is DTC P0651 indicated?

    YES 

    Go to step 4.

    NO 

    Go to step 3.

  3. Shorted part check

    -1. Check for Pending or Confirmed DTCs with the HDS while reconnecting these parts, one at a time:

    • APP sensor
    • Throttle body
    • Rocker arm oil pressure sensor
    • Input shaft (mainshaft) speed sensor
    DTC Description Confirmed DTC Pending DTC Freeze Frame
    P0651 Sensor Reference Voltage B Malfunction      

    Is DTC P0651 indicated?

    YES 

    Replace the part that caused the DTC when it was reconnected.

    NO 

    Check for poor connections or loose terminals at the PCM and the following parts, then go to step 1.

    • APP sensor
    • Throttle body
    • Rocker arm oil pressure sensor
    • Input shaft (mainshaft) speed sensor
  4. Shorted wire check (VCC lines to power)

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

    - 2. Jump the SCS line with the HDS.

    - 3. Disconnect the following connectors.

    PCM connector A (51P) - Refer to: How to Troubleshoot the A/T System (2014 2015), or How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016)
    PCM connector B (51P) - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015), or How to Troubleshoot the Fuel and Emissions Systems

    - 4. Turn the vehicle to the ON mode.

    - 5. Check for continuity between these test points and body ground individually.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    Throttle body 6P connector: disconnected
    Rocker arm oil pressure sensor 3P connector: disconnected
    Input shaft (mainshaft) speed sensor 3P connector: disconnected
    PCM connector A (51P): disconnected
    PCM connector B (51P): disconnected
    Connector Test circuit Terminal
    PCM connector B (51P) VCC2 No. 43 (GRN)
    PCM connector A (51P) VCC4 No. 42 (LT BLU)
    PCM connector B (51P) VCC5 No. 44 (BLU)
    GHH319282Courtesy of HONDA, U.S.A., INC.
    GHH319283Courtesy of HONDA, U.S.A., INC.

    Is there about 5.2V or more?

    YES 

    Repair a short to power in the VCC wire between the PCM (A42, B43, or B44) and each part that was disconnected in step 2.

    NO 

    Go to step 5.

  5. Shorted wire check (VCC lines)

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

    - 2. Check for continuity between these test points and body ground individually.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    Throttle body 6P connector: disconnected
    Rocker arm oil pressure sensor 3P connector: disconnected
    Input shaft (mainshaft) speed sensor 3P connector: disconnected
    PCM connector A (51P): disconnected
    PCM connector B (51P): disconnected
    Connector Test circuit Terminal
    PCM connector B (51P) VCC2 No. 43 (GRN)
    PCM connector A (51P) VCC4 No. 42 (LT BLU)
    PCM connector B (51P) VCC5 No. 44 (BLU)
    GHH319284Courtesy of HONDA, U.S.A., INC.
    GHH319285Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the VCC wire between the PCM (A42, B43, or B44) and each part that was disconnected in step 2.

    NO 

    The VCC wires are OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .