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Home >> Honda >> 2021 >> Accord Touring >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System / Engine Mechanical - Service, Testing & Troubleshooting (Except Hybrid) >> Troubleshooting >> PCM Power and Ground Circuit Troubleshooting (2.0 L Engine)

PCM Power and Ground Circuit Troubleshooting (2.0 L Engine)

PCM Power and Ground Circuit Troubleshooting 

  1. Engine starting check

    -1. Try to start the engine.

    Does the engine start and idle smoothly?

    YES 

    Go to the troubleshooting for CAN gateway system DTC (s) .

    NO 

    Go to step 2.

  2. Body electrical system DTC check

    -1. Check for body electrical system DTCs with the HDS.

    DTC Description DTC
       

    Are any DTCs indicated?

    YES 

    Go to the troubleshooting for the body electrical system DTC (s) .

    NO 

    Go to step 3.

  3. Fuse check 1

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

    -2. Check the following fuse.

    Fuse No. A15

    Is the fuse OK?

    YES 

    Go to step 4.

    NO 

    Go to step 5.

  4. Determine possible failure area (+B BACKUP FI-ECU line, others)

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

    -2. Disconnect the following connector.

    PCM connector A (50P)

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
    Test point 1 PCM connector A (50P) No. 7 
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 6.

    NO 

    Repair an open in the +B BACKUP FI-ECU wire between PCM (A7) and the No. A15 fuse .

  5. Shorted wire check (+B BACKUP FI-ECU line)

    -1. Remove the blown No. A15 fuse .

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector A (50P)

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
    Test point 1 PCM connector A (50P) No. 7 
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the +B BACKUP FI-ECU wire between the PCM (A7) and the No. A15 fuse. Also replace the No. A15 fuse.

    NO 

    Go to step 6.

  6. Fuse check 2

    -1. Check the following fuse.

    Fuse No. A13

    Is the fuse OK?

    YES 

    Go to step 10.

    NO 

    Go to step 7.

  7. Shorted wire check (+B IGP line)

    -1. Remove the blown No. A13 fuse .

    -2. Remove the injector relay .

    -3. Disconnect the following connector.

    Relay circuit board connector C (22P)

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Injector relay: disconnected
    Relay circuit board connector C (22P): disconnected
    Test point 1 Injector relay 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH394563Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the +B IGP wire on the No. A13 fuse circuit. If the wire is OK, replace the under-hood fuse/relay box . Also replace the No. A13 fuse.

    NO 

    Go to step 8.

  8. Part (s) internal circuit check (short in FI MAIN RLY OUT line):

    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 A (50P)
    Test condition Vehicle OFF (LOCK) mode
    Relay circuit board connector C (22P): disconnected
    Injector relay: disconnected
    Test point 1 Relay circuit board connector C (22P) (female terminals) No. 10:
    Test point 2 Body ground
    GHH394565Courtesy 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, check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If the symptom/indication goes away and the PCM was substituted, replace the original PCM . Also replace the No. A13 fuse .

    NO 

    Parts are OK. Go to step 9.

  9. Shorted wire check (FI MAIN RLY OUT line):

    Disconnect the following parts or connectors:

    • PGM-FI main relay 2
    • PCM connector A (50P)

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

    Test condition Vehicle OFF (LOCK) mode
    Relay circuit board connector C (22P): disconnected
    PGM-FI main relay 2: disconnected
    Injector relay: disconnected
    PCM connector A (50P): disconnected
    Test point 1 Relay circuit board connector C (22P) (female terminals) No. 10:
    Test point 2 Body ground
    GHH394567Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the FI MAIN RLY OUT wire between the relay circuit board and each part. Also replace the No. A13 fuse .

    NO 

    The FI MAIN RLY OUT wire is OK. Replace the relay circuit board . Also replace the No. A13 fuse .

  10. Fuse check 3

    -1. Check the following fuse.

    Fuse No. A40

    Is the fuse OK?

    YES 

    Go to step 14.

    NO 

    Go to step 11.

  11. Relay check

    -1. Remove PGM-FI main relay 2 .

    -2. Test PGM-FI main relay 2 .

    Is the relay OK?

    YES 

    Go to step 12.

    NO 

    Replace PGM-FI main relay 2. Also replace the No. A40 fuse .

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

    -1. Remove the blown No. A40 fuse .

    Disconnect the following parts or connectors:

    -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 (50P): disconnected
    No. A44 fuse: removed
    Body control module connector A (66P): disconnected
    Test point 1 PGM-FI main relay 2 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH394569Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the IG1 FUEL PUMP wire between PGM-FI main relay 2 and the No. A40 fuse. Also replace the No. A40 fuse.

    NO 

    Go to step 13.

  13. Shorted wire check (FUEL PUMP RLY OUT line)

    -1. Disconnect the following connector.

    Fuel tank unit 4P connector

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

    Test condition Vehicle OFF (LOCK) mode
    PGM-FI main relay 2: disconnected
    PCM connector A (50P): disconnected
    No. A44 fuse: removed
    Body control module connector A (66P): disconnected
    Fuel tank unit 4P connector: disconnected
    Test point 1 Fuel tank unit 4P connector (female terminals) No. 1:
    Test point 2 Body ground
    GHH394571Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the FUEL PUMP RLY OUT wire between PGM-FI main relay 2 and the fuel tank unit. Also replace the No. A40 fuse .

    NO 

    The FUEL PUMP RLY OUT wire is OK. Check the fuel pump, and replace it if needed. Also replace the No. A40 fuse .

  14. Open wire check (IG1 FUEL PUMP line)

    -1. Remove PGM-FI main relay 2 .

    -2. Exit the SCS mode with the HDS.

    -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 (50P): disconnected
      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
    GHH394573Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 15.

    NO 

    Repair an open in the IG1 FUEL PUMP wire between the No. A40 fuse and PGM-FI main relay 2.

  15. Fuse check 4

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

    -2. Check the following fuse.

    Fuse No. A44

    Is the fuse OK?

    YES 

    Go to step 17.

    NO 

    Go to step 16.

  16. Shorted wire check (IG1/IG1 MON line)

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

    -2. Disconnect the following connector.

    PCM connector E (80P)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    PCM connector E (80P): disconnected
    PGM-FI main relay 2: disconnected
    Test point 1 PCM connector E (80P) No. 36 
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the IG1/IG1 MON wire between the PCM (E36) and the No. A44 fuse . Also replace the No. A44 fuse.

    NO 

    The IG1/IG1 MON wire is not shorted. Go to step 18.

  17. Open wire check (IG1/IG1 MON line)

    -1. Reinstall the No. A44 fuse in the under-hood fuse/relay box .

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector E (80P)

    -4. Turn the vehicle to the ON mode.

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

    Test condition Vehicle ON mode
    PCM connector A (50P): disconnected
    PCM connector E (80P): disconnected
    PGM-FI main relay 2: disconnected
    Test point 1 PCM connector E (80P) No. 36 
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 18.

    NO 

    Repair an open in the IG1/IG1 MON wire between the PCM (E36) and the No. A44 fuse.

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

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

    -2. Reinstall PGM-FI main relay 2.

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    PCM connector E (80P): disconnected
    Test point 1 PCM connector A (50P) No. 5 
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 21.

    NO 

    Go to step 19.

  19. Open wire check (+B IGP line)

    -1. Disconnect the following connector.

    Relay circuit board connector C (22P)

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
      PCM connector E (80P): disconnected
      Relay circuit board connector C (22P): disconnected
    Test point 1 Relay circuit board connector C (22P) (female terminals) No. 11:
    Test point 2 Body ground
    GHH394575Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 20.

    NO 

    Repair an open in the +B IGP wire between the relay circuit board and the No. A13 fuse .

  20. Open wire check (FI MAIN RLY CL- line)

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

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
      PCM connector E (80P): disconnected
      Relay circuit board connector C (22P): disconnected
    Test point 1 Relay circuit board connector C (22P) (female terminals) No. 13:
    Test point 2 PCM connector A (50P) No. 5 
    GHH394577Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The FI MAIN RLY CL- wire is OK. Remove and test the relay circuit board . If the relay circuit board is OK, check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM .

    NO 

    Repair an open in the FI MAIN RLY CL- wire between the PCM (A5) and the relay circuit board.

  21. Open wire check (FI MAIN RLY OUT line)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    PCM connector E (80P): disconnected
    Relay circuit board connector C (22P): disconnected
    Test point 1 Relay circuit board connector C (22P) (female terminals) No. 10:
    Test point 2 PCM connector A (50P) No. 8 
    GHH394579Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 22.

    NO 

    Repair an open in the FI MAIN RLY OUT wire between the PCM (A8) and the relay circuit board.

  22. Relay circuit board check

    -1. Remove and test the relay circuit board .

    Is the relay circuit board OK?

    YES 

    Go to step 23.

    NO 

    Replace the relay circuit board .

  23. Open wire check (GND lines)

    -1. Check for continuity between the following test points and body ground individually.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
      PCM connector E (80P): disconnected
      Relay circuit board: removed
    Connector Terminal
    PCM connector A (50P)  No. 13
    Connector Terminal
    PCM connector E (80P)  No. 7
    No. 8
    No. 22
    No. 23
    No. 24

    Is there continuity?

    YES 

    The FI ECU GND, GND2, GND3, GND4, GND5 (INJ GND1), GND6 (INJ GND2) wires are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM .

    NO 

    Repair an open in the FI ECU GND, GND5 (INJ GND1), or GND6 (INJ GND2) wire between the PCM (A13, E7, E8) and G102, or an open in the GND2, GND3, or GND4 wire between the PCM (E22, E23, E24) and G101.

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