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Home >> Acura >> 2017 >> MDX Base >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control And Engine Mechanical - Service, Testing And Troubleshooting (Except Hybrid) >> Troubleshooting >> PCM Power and Ground Circuit Troubleshooting (2017 2018 2019 2020)

PCM Power and Ground Circuit Troubleshooting (2017 2018 2019 2020)

PCM Power and Ground Circuit Troubleshooting 

  1. Engine starting check (Without CAN Gateway model only)

    -1. Try to start the engine.

    Does the engine start and idle smoothly?

    YES 

    Go to the F-CAN circuit troubleshooting - Refer to: F-CAN Circuit Troubleshooting(Without CAN Gateway) (2016), or F-CAN Circuit Troubleshooting (2017 2018), or F-CAN Circuit Troubleshooting (2014 2015) .

    NO 

    Go to step 2.

  2. Fuse check

    -1. Check the following fuse.

    Fuse No. C10 (15 A)
    Location Under-hood fuse/relay box

    Is the fuse OK?

    YES 

    Go to step 6.

    NO 

    Go to step 3.

  3. Shorted wire check

    -1. Remove the blown No. C10 (15 A) fuse from the under-hood fuse/relay box.

    - 2. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.

    GHH320194Courtesy of HONDA, U.S.A., INC.

    - 3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PGM-FI main relay 1: disconnected
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH320197Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the +B IGP(15A) wire between the No. C10 (15 A) fuse and PGM-FI main relay 1. If the wire is OK, replace the under-hood fuse/relay box . Also replace the No. C10 (15 A) fuse.

    NO 

    Go to step 4.

  4. Part(s) internal circuit check (short in IGP line)

    -1. Disconnect each of the parts or connectors below, one at a time, then check for continuity between test points 1 and 2.

    • PGM-FI main relay 2
    • PCM connector B (51P)
    • CMP sensor 3P connector
    • CKP sensor 3P connector
    • Injector relay
    • Electronic throttle control system (ETCS) control relay
    Test condition Vehicle OFF (LOCK) mode
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 2:
    Test point 2 Body ground
    GHH320199Courtesy of HONDA, U.S.A., INC.

    Does continuity go away when one of the above components is disconnected?

    YES 

    Replace the part that made the short to body ground go away when it was disconnected. If the part is the PCM, substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) , then recheck. If the symptom/indication goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) . Also replace the No. C10 (15 A) fuse in the under-hood fuse/relay box.

    NO 

    Parts are OK. Go to step 5.

  5. Shorted wire check (IGP line)

    -1. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 2. Disconnect the following parts or connectors:

    • PGM-FI main relay 2
    • PCM connector B (51P)
    • CMP sensor
    • CKP sensor
    • Injector relay
    • Electronic throttle control system (ETCS) control relay
    • Radiator fan relay

    - 3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PGM-FI main relay 1: disconnected
      PGM-FI main relay 2: disconnected
      PCM connector B (51P): disconnected
      CMP sensor 3P connector: disconnected
      CKP sensor 3P connector: disconnected
      Injector relay: disconnected
      Electronic throttle control system (ETCS) control relay: disconnected
      Radiator fan relay: disconnected
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 2:
    Test point 2 Body ground
    GHH320201Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the IGP wire between PGM-FI main relay 1 and each part. Also replace the No. C10 (15 A) fuse in the under-hood fuse/relay box.

    NO 

    The IGP wire is OK. Replace PGM-FI main relay 1. Also replace the No. C10 (15 A) fuse in the under-hood fuse/relay box.

  6. Fuse check 2

    -1. Check the following fuse.

    Fuse No. D21 (20 A)
    Location Driver's under-dash fuse/relay box

    Is the fuse OK?

    YES 

    Go to step 11.

    NO 

    Go to step 7.

  7. Relay check

    -1. Remove the blown No. D21 (20 A) fuse from the driver's under-dash fuse/relay box.

    - 2. Remove PGM-FI main relay 2 (A) from the driver's under-dash fuse/relay box.

    GHH320202Courtesy of HONDA, U.S.A., INC.

    - 3. Test PGM-FI main relay 2.

    Is the relay OK?

    YES 

    PGM-FI main relay 2 is OK. Go to step 8.

    NO 

    Replace PGM-FI main relay 2. Also replace the No. D21 (20 A) fuse in the driver's under-dash fuse/relay box.

  8. Determine possible failure area (IG1 FUEL PUMP line, others)

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PGM-FI main relay 2: disconnected
    Test point 1 PGM-FI main relay 2 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH320204Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 9.

    NO 

    Go to step 10.

  9. Shorted wire check (IG1 FUEL PUMP line)

    -1. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 2. Disconnect the following connector.

    PCM connector A (51P)

    - 3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PGM-FI main relay 2: disconnected
      PCM connector A (51P): disconnected
    Test point 1 PCM connector A (51P) No. 18 - Refer to: PCM Connector for Inputs and Outputs (2017 2018 2019 2020),  or PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016) 
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the IG1 FUEL PUMP wire between the No. D21 (20 A) fuse in the driver's under-dash fuse/relay box and the PCM (A18).

    NO 

    The IG1 FUEL PUMP wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) . Also replace the No. D21 (20 A) fuse in the under-dash fuse/relay box.

  10. Shorted wire check (IGP line)

    -1. Disconnect the following connector.

    Fuel pump control module 6P connector

    - 2. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PGM-FI main relay 2: disconnected
      Fuel pump control module 6P connector: disconnected
    Test point 1 PGM-FI main relay 2 4P socket (female terminals) No. 2:
    Test point 2 Body ground
    GHH320206Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the IGP wire between PGM-FI main relay 2 and the fuel pump control module 6P connector. Also replace the No. D21 (20 A) fuse in the driver's under-dash fuse/relay box.

    NO 

    The IGP wire is OK. Check the fuel pump, and replace it if needed. Also replace the No. D21 (20 A) fuse in the driver's under-dash fuse/relay box.

  11. Open wire check (IG1 FUEL PUMP line)

    -1. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 2. Disconnect the following connector.

    PCM connector A (51P)

    - 3. Turn the vehicle to the ON mode.

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

    Test condition Vehicle ON mode
      PCM connector A (51P): disconnected
    Test point 1 PCM connector A (51P) No. 18 - Refer to: PCM Connector for Inputs and Outputs (2017 2018 2019 2020),  or PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016) 
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    The IG1 FUEL PUMP wire is OK. Go to step 12.

    NO 

    Repair an open in the IG1 FUEL PUMP wire between the No. D21 (20 A) fuse in the driver's under-dash fuse/relay box and the PCM (A18).

  12. Determine possible failure area (PGM-FI main relay 1 control circuit, others)

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

    Test condition Vehicle ON mode
      PCM connector A (51P): disconnected
    Test point 1 PCM connector A (51P) No. 7 - Refer to: PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016),  or PCM Connector for Inputs and Outputs (2017 2018 2019 2020) 
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 15.

    NO 

    Go to step 13.

  13. Open wire check (+B IGP(15A) line)

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

    - 2. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.

    GHH320207Courtesy of HONDA, U.S.A., INC.

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (51P): disconnected
      PGM-FI main relay 1: disconnected
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH320209Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 14.

    NO 

    Repair an open in the +B IGP(15A) wire between PGM-FI main relay 1 and the No. C10 (15 A) fuse in the driver's under-dash fuse/relay box. If the wire is OK, replace the under-hood fuse/relay box . Also replace the No. C10 (15 A) fuse.

  14. Open wire check (M RLY line)

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (51P): disconnected
      PGM-FI main relay 1: disconnected
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 4:
    Test point 2 PCM connector A (51P) No. 7 - Refer to: PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016),  or PCM Connector for Inputs and Outputs (2017 2018 2019 2020) 
    GHH320211Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The M RLY wire is OK. Test PGM-FI main relay 1 - Refer to: Power Relay Test (2016), or Power Relay Test (2014 2015) . If the relay is OK, check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

    NO 

    Repair an open in the M RLY wire between the PCM (A7) and PGM-FI main relay 1.

  15. Open wire check (+B IGP(15A) line)

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

    - 2. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.

    GHH320212Courtesy of HONDA, U.S.A., INC.

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (51P): disconnected
      PGM-FI main relay 1: disconnected
    Test point 1 PGM-FI main relay 1 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH320214Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 16.

    NO 

    Replace the under-hood fuse/relay box .

  16. Open wire check (IGP line)

    -1. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 2. Disconnect the following connector.

    PCM connector B (51P)

    - 3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (51P): disconnected
      PCM connector B (51P): disconnected
      PGM-FI main relay 1: disconnected
    Test point 1 PGM-FI main relay 1 4P socket terminal (female terminals) No. 2:
    Test point 2 PCM connector B (51P) No. 10 - Refer to: PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016),  or PCM Connector for Inputs and Outputs (2017 2018 2019 2020) 
    GHH320216Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The IGP wire is OK. Go to step 17.

    NO 

    Repair an open in the IGP wire between the PCM (B10) and PGM-FI main relay 1.

  17. Relay check

    -1. Test PGM-FI main relay 1.

    Is PGM-FI main relay 1 OK?

    YES 

    PGM-FI main relay 1 is OK. Go to step 18.

    NO 

    Replace PGM-FI main relay 1.

  18. Open wire check (GND1, GND2 LG, GND3, PGM lines)

    -1. Disconnect the following connector.

    PCM connector C (51P)

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (51P): disconnected
      PCM connector B (51P): disconnected
      PCM connector C (51P): disconnected
      PGM-FI main relay 1: disconnected
    Connector Terminal
    PCM connector B (51P) - Refer to: PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016),  or PCM Connector for Inputs and Outputs (2017 2018 2019 2020)  No. 11
    No. 20
    PCM connector C (51P) - Refer to: PCM Connector for Inputs and Outputs (2017 2018 2019 2020),  or PCM Connector for Inputs and Outputs (2014 2015),  or PCM Connector for Inputs and Outputs (2016)  No. 1
    No. 20

    Is there continuity?

    YES 

    The GND1, GND2 LG, GND3, and PGM wires are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

    NO 

    Repair an open in the GND1, GND2 LG, GND3, and/or PGM wire between the PCM (B11, B20, C1, C20) and G101.

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