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Home >> Honda >> 2005 >> Pilot EX >> Repair and Diagnosis >> Engine Performance >> System >> Electronic Throttle Control System >> DTC Troubleshooting >> DTC P1659: Electronic Throttle Control System (ETCS) Control Relay OFF Malfunction
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DTC P1659: Electronic Throttle Control System (ETCS) Control Relay OFF Malfunction

  1. Turn the ignition switch ON (II).
  2. Clear the DTC with the HDS.
  3. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC P1659 indicated? 

    YES  - Go to step 4.

    NO  - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM.

  4. Turn the ignition switch OFF.
  5. Check the No. 7 DBW (throttle actuator control) (15 A) fuse in under-hood subfuse box.

    Is the fuse OK? 

    YES  - Go to step 6.

    NO  - Go to step  20.

  6. Remove the electronic throttle control system (ETCS) control relay (A).
    Fig 1: Removing Electronic Throttle Control System (ETCs) Control Relay
    G04546074Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Test the electronic throttle control system (ETCS) control relay (see POWER RELAY TEST ).

    Is the electronic throttle control system (ETCS) control relay OK? 

    YES  - Go to step 8.

    NO  - Replace the electronic throttle control system (ETCS) control relay, then go to step  28.

  8. Turn the ignition switch ON (II).
  9. Measure voltage between electronic throttle control system (ETCS) control relay connector terminal No. 4 and body ground.
    Fig 2: Measuring Voltage Between Electronic Throttle Control System (ETCs) Control Relay Connector Terminal No. 4 And Body Ground
    G04546075Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step 10.

    NO  - Repair open in the wire between PGM-FI main relay 1 (FI MAIN) and the electronic throttle control system (ETCS) control relay, then go to step  27.

  10. Measure voltage between electronic throttle control system (ETCS) control relay connector terminal No. 1 and body ground.
    Fig 3: Measuring Voltage Between Electronic Throttle Control System (ETCs) Control Relay Connector Terminal No. 1 And Body Ground
    G04546076Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step 11.

    NO  - Repair open in the wire between electronic throttle control system (ETCS) control relay and under-hood subfuse box, then go to step  27.

  11. Turn the ignition switch OFF.
  12. Jump the SCS line with the HDS.
  13. Disconnect PCM connector C (44P).
  14. Connect electronic throttle control system (ETCS) control relay connector terminal No. 2 to body ground with a jumper wire.
    Fig 4: Connecting (ETCs) Control Relay Connector Terminal No. 2 To Body Ground With Jumper Wire
    G04546077Courtesy of AMERICAN HONDA MOTOR CO., INC.
  15. Check for continuity between PCM connector terminal C4 and body ground.
    Fig 5: Checking Continuity Between PCM Connector Terminal C4 And Body Ground
    G04546078Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 16.

    NO  - Repair open in the wire between the PCM (C4) and the electronic throttle control system (ETCS) control relay, then go to step  28.

  16. Disconnect the jumper wire.
  17. Disconnect PCM connector A (44P).
  18. Connect electronic throttle control system (ETCS) control relay connector terminal No. 3 to body ground with a jumper wire.
    Fig 6: Connecting (ETCs) Control Relay Connector Terminal No. 3 To Body Ground With Jumper Wire
    G04546079Courtesy of AMERICAN HONDA MOTOR CO., INC.
  19. Check for continuity between PCM connector terminal A20 and body ground.
    Fig 7: Checking Continuity Between PCM Connector Terminal A20 And Body Ground
    G04546080Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  33.

    NO  - Repair open in the wire between the PCM (A20) and the electronic throttle control system (ETCS) control relay, then go to step  28.

  20. Remove the blown No. 7 DBW (throttle actuator control) (15 A) fuse in under-hood subfuse box.
  21. Jump the SCS line with the HDS.
  22. Disconnect PCM connector C (44P).
  23. Check for continuity between PCM connector terminal C4 and body ground.
    Fig 8: Checking Continuity Between PCM Connector Terminal C4 And Body Ground
    G04546081Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 24.

    NO  - Replace the No. 7 DBW (throttle actuator control) (15 A) fuse, then go to step  28.

  24. Remove the electronic throttle control system (ETCS) control relay (A).
    Fig 9: Removing Electronic Throttle Control System (ETCs) Control Relay
    G04546082Courtesy of AMERICAN HONDA MOTOR CO., INC.
  25. Check for continuity between PCM connector terminal C4 and body ground.
    Fig 10: Checking Continuity Between PCM Connector Terminal C4 And Body Ground
    G04546083Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the electronic throttle control system (ETCS) control relay and the PCM (C4), then go to step  28.

    NO  - Go to step 26.

  26. Check for continuity between electronic throttle control system (ETCS) control relay connector terminal No. 1 and body ground.
    Fig 11: Checking Continuity Between (ETCs) Control Relay Connector Terminal No. 1 And Body Ground
    G04546084Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the No. 7 DBW (throttle actuator control) (15 A) fuse and electronic throttle control system (ETCS) control relay, then go to step  28.

    NO  - Replace the No. 7 DBW (throttle actuator control) (15 A) fuse, then go to step  28.

  27. Turn the ignition switch OFF.
  28. Reconnect all connectors.
  29. Turn the ignition switch ON (II).
  30. Reset the PCM with the HDS.
  31. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  32. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    YES  - If DTC P1659 is indicated, check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM, then go to step  1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .

    NO  - Troubleshooting is complete.

  33. Update the PCM if it does not have the latest software, or substitute a known-good PCM (see PCM UPDATING AND SUBSTITUTION FOR TESTING ).
  34. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    YES  - If DTC P1659 is indicated, check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM, then go to step  1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .

    NO  - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ).

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