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Home >> Honda >> 2019 >> Pilot EX, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System / Engine Mechanical - Service, Testing & Troubleshooting >> Troubleshooting >> PCM POWER AND GROUND CIRCUIT (9-Speed A/T) (2019 2020 2021)

PCM POWER AND GROUND CIRCUIT (9-Speed A/T) (2019 2020 2021)

  1. Engine starting check

    -1. Start the engine.

    Does the engine start and idle smoothly?

    YES (without CAN gateway)

    Go to the F-CAN circuit troubleshooting - Go to:F-CAN Circuit Troubleshooting (9-Speed A/T) (2019 2020 2021) .

    YES (with CAN gateway)

    Go to step 2.

    NO 

    Go to step 3.

  2. CAN gateway system DTC check

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

    - 2. Turn the vehicle to the ON mode.

    - 3. Clear the DTC with the HDS.

    Clear DTC

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

    - 5. Turn the vehicle to the ON mode.

    - 6. Check for CAN gateway system DTCs with the HDS.

    DTC Description DTC
       

    DTC (CAN GATEWAY)

    Are any DTCs indicated?

    YES 

    Go to the Troubleshooting For Can Gateway System DTCs .

    NO 

    Intermittent failure, the system is OK at this time.

  3. Fuse check

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

    - 2. Check the following fuse.

    Fuse No. A21 - Refer to:
    Fuse to Components Index (WITH Auto Idle Stop System) (2019 2020 2021) or
    Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021) .

    Is the fuse OK?

    YES 

    Go to step 7.

    NO 

    Go to step 4.

  4. Shorted wire check (+B MAIN RLY line)

    -1. Remove the blown No. A21 fuse.

    - 2. Disconnect the following connector.

    Relay circuit board connector B (16P)

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

    Test condition Vehicle OFF (LOCK) mode
    Relay circuit board connector B (16P): disconnected
    Test point 1 Relay circuit board connector B (16P) No. 4
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the +B MAIN RLY wire between the No. A21 fuse and the relay circuit board. If the wire is OK, replace the Under-Hood Fuse/Relay Box - Removal and Installation . Also replace the No. A21 fuse.

    NO 

    Go to step 5.

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

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

    - 2. 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)
    • CMP sensor 3P connector
    • CKP sensor 3P connector
    • Radiator fan relay
    Test condition Vehicle OFF (LOCK) mode
    Relay circuit board connector B (16P): disconnected
    Test point 1 Relay circuit board connector B (16P) No. 8, No. 9, and No. 10
    Test point 2 Body ground

    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 - Go to: PCM (9-Speed A/T) (2019 2020 2021) , then recheck.

    If the symptom/indication goes away and the PCM was substituted, replace the original PCM - Go to: PCM (9-Speed A/T) (2019 2020 2021)

    Also replace the No. A21 fuse. - Refer to:

    Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

    Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

    NO 

    Parts are OK. Go to step 6.

  6. Shorted wire check (IGP line)

    -1. Disconnect the following parts or connectors:

    • PGM-FI main relay 2
    • PCM connector A (50P)
    • CMP sensor 3P connector
    • CKP sensor 3P connector
    • Radiator fan relay

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

    Test condition Vehicle OFF (LOCK) mode
    Relay circuit board connector B (16P): disconnected
    PGM-FI main relay 2: disconnected
    PCM connector A (50P): disconnected
    CMP sensor 3P connector: disconnected
    CKP sensor 3P connector: disconnected
    Radiator fan relay : disconnected
    Test point 1 Relay circuit board connector B (16P) No. 8, No. 9, and No. 10
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the IGP wire between the relay circuit board and each part. Also replace the No. A21 fuse. - Refer to:

    Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

    Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

    NO 

    The IGP wire is OK. Replace the Relay Circuit Board - Removal and Installation, . Also replace the No. A21 fuse.

  7. Fuse check 2

    -1. Check the following fuse.

    Fuse No. C6 - Refer to:

    Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

    Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

    Is the fuse OK?

    YES 

    Go to step 12.

    NO 

    Go to step 8.

  8. Relay check

    -1. Remove the blown No. C6 fuse.

    Fuse To Components Index (With Auto Idle Stop System) (2019 2020 2021) or

    Fuse To Components Index (Without Auto Idle Stop System) (2019 2020 2021) .

    - 2. Remove PGM-FI main relay 2. Power Relay (2019 2020 2021)

    - 3. Test PGM-FI main relay 2. Test (2019 2020 2021) .

    Is the relay OK?

    YES 

    PGM-FI main relay 2 is OK. Go to step 9.

    NO 

    Replace PGM-FI main relay 2. Also replace the No. C6 fuse.

  9. 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. 2: (1)
    Test point 2 Body ground
    GHH308385Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 10.

    NO 

    Go to step 11.

  10. Shorted wire check (IG1 FUEL PUMP line)

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

    SCS Short

    - 2. Disconnect the following connector.

    PCM connector A (50P)

    - 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
    Test point 1 PCM connector A (50P) No. 6 - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the IG1 FUEL PUMP wire between the PCM (A6) and the No. C6 fuse. - Refer to:

    Fuse To Components Index (WITH Auto Idle Stop System) (2019 2020 2021)

    Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021)

    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 - Go to: PCM (9-Speed A/T) - Removal and Installation (2019 2020 2021) . Also replace the No. C6 fuse.

  11. Shorted wire check (+B FUEL PUMP 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
    Fuel tank unit 4P connector: disconnected
    Test point 1 PGM-FI main relay 2 4P socket (female terminals) No. 1: (1)
    Test point 2 Body ground
    GHH308386Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the +B FUEL PUMP wire between PGM-FI main relay 2 and the Fuel tank unit. Also replace the No. C6 fuse. - Refer to:

    Fuse to Components Index (WITH Auto Idle Stop System) (2019 2020 2021) or

    Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021) .

    NO 

    The +B FUEL PUMP wire is OK. Check the fuel pump, and replace it Fuel Tank Unit - Removal and Installation if needed. Also replace the No. C6 fuse.

  12. Open wire check (IG1 FUEL PUMP line)

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

    SCS Short

    - 2. Disconnect the following connector.

    PCM connector A (50P)

    - 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
    Test point 1 PCM connector A (50P) No. 6 - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    The IG1 FUEL PUMP wire is OK. Go to step 13.

    NO 

    Repair an open in the IG1 FUEL PUMP wire between the PCM (A6) and the No. C6 fuse. - Refer to:

  13. Fuse to Components Index (WITH Auto Idle Stop System) (2019 2020 2021) or
  14. Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021) .
  15. 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 (50P): disconnected
    Test point 1 PCM connector A (50P) No. 22 - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 16.

    NO 

    Go to step 14.

  16. Open wire check (+B MAIN RLY line)

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

    - 2. Disconnect the following connector.

    Relay circuit board connector B (16P)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Relay circuit board connector B (16P): disconnected
    Test point 1 Relay circuit board connector B (16P) No. 4
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 15.

    NO 

    Repair an open in the +B MAIN RLY wire between the relay circuit board and the No. A21 fuse. - Refer to:

    Fuse to Components Index (WITH Auto Idle Stop System) (2019 2020 2021) or

    Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021) .

    If the wire is OK, replace the Under-Hood Fuse/Relay Box - Removal and Installation .

    Also replace the No. A21 fuse.

  17. Open wire check (M RLY line)

    -1. Disconnect the following connector.

    Relay circuit board connector A (10P)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Relay circuit board connector B (16P): disconnected
    Relay circuit board connector A (10P): disconnected
    Test point 1 Relay circuit board connector A (10P) No. 9
    Test point 2 PCM connector A (50P) No. 22 - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .

    Is there continuity?

    YES 

    The FI M RLY wire is OK. Remove and test Relay Circuit Board - Removal and Installation, Test . 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 - Go to: PCM (9-Speed A/T) - Removal and Installation (2019 2020 2021) .

    NO 

    Repair an open in the M RLY wire between the PCM (A22) and the relay circuit board.

  18. Open wire check (+B MAIN RLY line)

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

    - 2. Disconnect the following connector.

    Relay circuit board connector B (16P)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Relay circuit board connector B (16P): disconnected
    Test point 1 Relay circuit board connector B (16P) No. 4
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    Go to step 17.

    NO 

    Repair an open in the +B MAIN RLY wire between the relay circuit board and the No. A21 fuse. - Refer to:

    Fuse to Components Index (WITH Auto Idle Stop System) (2019 2020 2021) or

    Fuse to Components Index (WITHOUT Auto Idle Stop System) (2019 2020 2021) .

    If the wire is OK, replace the Under-Hood Fuse/Relay Box - Removal and Installation .

  19. Open wire check (IGP line)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Relay circuit board connector B (16P): disconnected
    Test point 1 Relay circuit board connector B (16P) No. 8
    Test point 2 PCM connector A (50P) No. 4 - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .

    Is there continuity?

    YES 

    The IGP wire is OK. Go to step 18.

    NO 

    Repair an open in the IGP wire between the PCM (A4) and the relay circuit board.

  20. Relay circuit board check

    -1. Remove and test the relay circuit board.Relay Circuit Board - Removal and Installation, Test .

    Is the relay circuit board OK?

    YES 

    Go to step 19.

    NO 

    Replace the Relay Circuit Board - Removal and Installation .

  21. Open wire check (GND1, GND2 LG, GND3, GND4, GND5, PGM lines)

    -1. Disconnect the following connector.

    PCM connector E (80P)

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

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Relay circuit board connector B (16P): disconnected
    PCM connector E (80P): disconnected
    Connector Terminal
    PCM connector E (80P) - Refer to:
    PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .    		 No. 8, 15, 22, 25, 26, 27

    Is there continuity?

    YES 

    The GND1, GND2 LG, GND3, GND4, GND5, 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 - Go to:PCM (9-Speed A/T) - Removal and Installation (2019 2020 2021) .

    NO 

    Repair an open in the GND1, GND2 LG, GND3, GND4, GND5, and/or PGM wire between the PCM (E8, E15, E22, E25, E26, E27) and G101.

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