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Home >> Acura >> 2012 >> ZDX >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI System >> PCM Power and Ground Circuit Troubleshooting
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PCM Power and Ground Circuit Troubleshooting

  1. Check the No. 3-1 IG MAIN (50 A) fuse in the under-hood fuse/relay box.

    Is the fuse OK? 

    YES  -Repair an open in the wire between the No. 3-1 IG MAIN (50 A) fuse and the ignition switch (without keyless access) or power control unit (with keyless access). If the wire is OK, go to step 2.

    NO  -Repair a short in the wire between the No. 3-1 IG MAIN (50 A) fuse and the ignition switch (without keyless access) or power control unit (with keyless access). Also replace the No. 3-1 IG MAIN (50 A) fuse.

  2. Inspect the No. 17 Fl MAIN (15 A) fuse in the under-hood fuse/relay box.

    Is the fuse OK? 

    YES  -Go to step  9.

    NO  -Go to step 3.

  3. Remove the blown No. 17 Fl MAIN (15 A) fuse from the under-hood fuse/relay box.
  4. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.
    Fig 1: Identifying PGM-FI Main Relay 1 Of Under-Hood Fuse/Relay Box
    G08075635Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. Check for continuity between body ground and PGM-FI main relay 1 4P connector terminals No. 1 and No. 4 individually.
    Fig 2: Checking Continuity Between Body Ground And PGM-FI Main Relay 1 4P Connector Terminals No. 1 And 4
    G08075636Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ). Also replace the No. 17 Fl MAIN (15 A) fuse.

    NO  -Go to step 6.

  6. While disconnecting each of the parts or connectors below, one at a time, check for continuity between PGM-FI main relay 1 4P connector terminal No. 2 and body ground:
    • PGM-FI main relay 2
    • PCM connector B (49P)
    • Each injector 2P connector
    • CMP sensor 3P connector
    • CKP sensor 3P connector
    • MAF sensor/IAT sensor 5P connector
    • Electronic throttle control system (ETCS) control relay
      Fig 3: Checking Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No. 2 And Body Ground
      G08075637Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Does continuity go away when one of the above parts or connectors is disconnected? 

    YES  -Replace the part that made the short to body ground go away when disconnected. If the part is the PCM, update the PCM if it does not have the latest software (see PCM UPDATE  ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT  ). Also replace the No. 17 Fl MAIN (15 A)fuse.

    NO  -Go to step 7.

  7. Disconnect the connectors from these parts:
    • PGM-FI main relay 2
    • PCM (connector B (49P))
    • Injectors
    • CMP sensor
    • CKP sensor
    • MAF sensor/IAT sensor
    • Electronic throttle control system (ETCS) control relay
  8. Check for continuity between PGM-FI main relay 1 4P connector terminal No. 2 and body ground.
    Fig 4: Checking Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No. 2 And Body Ground
    G08075638Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between PGM-FI main relay 1 and each part. Also replace the No. 17 Fl MAIN (15A)fuse.

    NO  -Replace PGM-FI main relay 1. Also replace the No. 17 FI MAIN (15A)fuse.

  9. Inspect the No. 9 FUEL PUMP (20 A) fuse in the Driver's under-dash fuse/relay box.

    Is the fuse OK? 

    YES  -Go to step  19.

    NO  -Go to step 10.

  10. Remove the blown No. 9 FUEL PUMP (20 A) fuse from the Driver's under-dash fuse/relay box.
  11. Remove the Driver's dashboard undercover (see DRIVER'S DASHBOARD UNDERCOVER REMOVAL/INSTALLATION ), then remove PGM-FI main relay 2 (A) from the Driver's under-dash fuse/relay box.
    Fig 5: Identifying PGM-FI Main Relay 2 Of Driver's Under-Dash Fuse/Relay Box
    G08075639Courtesy of AMERICAN HONDA MOTOR CO., INC.
  12. Test PGM-FI main relay 2 (see POWER RELAY TEST ).

    Is the relay OK? 

    YES  -Go to step 13.

    NO  -Replace PGM-FI main relay 2. Also replace the No. 9 FUEL PUMP (20 A) fuse.

  13. Check for continuity between PGM-FI main relay 2 4P connector terminal No. 2 and body ground.
    Fig 6: Checking Continuity Between PGM-FI Main Relay 2 4P Connector Terminal No. 2 And Body Ground
    G08075640Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 14.

    NO  -Go to step  17.

  14. Jump the SCS line with the HDS.
  15. Disconnect PCM connector B (49P).
  16. Check for continuity between PCM connector terminal B42 and body ground.
    Fig 7: Checking Continuity Between PCM Connector Terminal B42 And Body Ground
    G08075641Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the No. 9 FUEL PUMP (20 A) fuse and the PCM (B42), between the No. 9 FUEL PUMP (20 A) fuse and PGM-FI main relay 2, or between the No. 9 FUEL PUMP (20 A) fuse and the immobilizer control unit. Also replace the No. 9 FUEL PUMP (20 A) fuse.

    NO  -Replace the No. 9 FUEL PUMP (20 A) fuse, and update the PCM if it does not have the latest software (see PCM UPDATE  ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT  ).

  17. Disconnect the fuel pump control module 10P connector (see FUEL PUMP CONTROL MODULE REPLACEMENT ).
  18. Check for continuity between fuel pump control module 10P connector terminal No. 3 and body ground.
    Fig 8: Checking Continuity Between Fuel Pump Control Module 10P Connector Terminal No. 3 And Body Ground
    G08075642Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the fuel pump control module and PGM-FI main relay 2. Also replace the No. 9 FUEL PUMP (20 A) fuse.

    NO  -Replace the No. 9 FUEL PUMP (20 A) fuse, and substitute a known-good fuel pump control module (see FUEL PUMP CONTROL MODULE REPLACEMENT ), then recheck. If the symptom/indication goes away with a known-good fuel pump control module, replace the original fuel pump control module (see FUEL PUMP CONTROL MODULE REPLACEMENT ).

  19. Jump the SCS line with the HDS.
  20. Disconnect PCM connectors A (49P) and B (49P).
  21. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  22. Measure the voltage between PCM connector terminal B42 and body ground.
    Fig 9: Measuring Voltage Between PCM Connector Terminal B42 And Body Ground
    G08075643Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 23.

    NO  -Repair an open in the wire between the No. 9 FUEL PUMP (20 A) fuse and the PCM (B42).

  23. Measure the voltage between PCM connector terminal A6 and body ground.
    Fig 10: Measuring Voltage Between PCM Connector Terminal A6 And Body Ground
    G08075644Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step  28.

    NO  -Go to step 24.

  24. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  25. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.
    Fig 11: Identifying PGM-FI Main Relay 1 Of Under-Hood Fuse/Relay Box
    G08075645Courtesy of AMERICAN HONDA MOTOR CO., INC.
  26. Measure the voltage between PGM-FI main relay 1 4P connector terminal No. 4 and body ground.
    Fig 12: Measuring Voltage Between PGM-FI Main Relay 1 4P Connector Terminal No. 4 And Body Ground
    G08075646Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 27.

    NO  -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ).

  27. Check for continuity between PGM-FI main relay 1 4P connector terminal No. 3 and PCM connector terminal A6.
    Fig 13: Checking Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No. 3 And PCM Connector Terminal A6
    G08075647Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Test PGM-FI main relay 1 (see POWER RELAY TEST ). If the relay is OK, update the PCM if it does not have the latest software (see PCM UPDATE  ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT  ).

    NO  -Repair an open in the wire between the PCM (A6) and PGM-FI main relay 1.

  28. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  29. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.
    Fig 14: Identifying PGM-FI Main Relay 1 Of Under-Hood Fuse/Relay Box
    G08075648Courtesy of AMERICAN HONDA MOTOR CO., INC.
  30. Measure the voltage between PGM-FI main relay 1 4P connector terminal No. 1 and body ground.
    Fig 15: Measuring Voltage Between PGM-FI Main Relay 1 4P Connector Terminal No. 1 And Body Ground
    G08075649Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 31.

    NO  -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ).

  31. Check for continuity between PGM-FI main relay 1 4P connector terminal No. 2 and PCM connector terminal B3.
    Fig 16: Checking Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No. 2 And PCM Connector Terminal B3
    G08075650Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 32.

    NO  -Repair an open in the wire between the PCM (B3) and PGM-FI main relay 1.

  32. Test PGM-FI main relay 1 (see POWER RELAY TEST ).

    Is PGM-FI main relay 1 OK? 

    YES  -Go to step 33.

    NO  -Replace PGM-FI main relay 1.

  33. Disconnect PCM connectors A (49P), B (49P), and C (49P).
  34. Check for continuity between body ground and PCM connector terminals A41, B1, B40, B41, C1, and C41 individually.
    Fig 17: Checking Continuity Between Body Ground And PCM Connector Terminals A41
    G08075651Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 18: Checking Continuity Between Body Ground And PCM Connector Terminals B1, B40 And B41
    G08075652Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 19: Checking Continuity Between Body Ground And PCM Connector Terminals C1 And C41
    G08075653Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Update the PCM if it does not have the latest software (see PCM UPDATE  ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT  ).

    NO  -Repair an open in the wire(s) between the PCM (A41, B1, B40, B41, C1, C41) and body ground (G101).

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