LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Acura >> 2014 >> TSX Special Edition, Standard Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Electronic Throttle Control System (4-CYL) >> DTC Troubleshooting >> DTC P1659: ETCS Control Relay OFF Malfunction
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P1659: ETCS Control Relay OFF Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Turn the ignition switch to ON (II).
  2. Clear the DTC with the HDS.
  3. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1659 indicated? 

    YES  -Go to step 4.

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

  4. Turn the ignition switch to LOCK (0).
  5. Check the No. 18 DBW (ETCS) (15 A) fuse in the under-hood fuse/relay box.

    Is the fuse OK? 

    YES  -Go to step 6.

    NO  -Go to step  17.

  6. Remove the ETCS control relay (A) from the under-hood fuse/relay box.
    Fig 1: Identifying ETCS Control Relay
    G07767826Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Test the ETCS control relay (see POWER RELAY TEST ).

    Is the ETCS control relay OK? 

    YES  -Go to step 8.

    NO  -Replace the ETCS control relay, then go to step  23.

  8. Turn the ignition switch to ON (II).
  9. Measure the voltage between ETCS control relay 4P connector terminal No. 4 and body ground.
    Fig 2: Measuring Voltage Between ETCS Control Relay 4P Connector Terminal No. 4 And Body Ground
    G07767827Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 10.

    NO  -Check the under-hood fuse/relay box, and replace it if needed (see REMOVAL AND INSTALLATION ), then go to step  22.

  10. Measure the voltage between ETCS control relay 4P connector terminal No. 1 and body ground.
    Fig 3: Measuring Voltage Between ETCS Control Relay 4P Connector Terminal No. 1 And Body Ground
    G07767828Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 11.

    NO  -Check the under-hood fuse/relay box, and replace it if needed (see REMOVAL AND INSTALLATION ), then go to step  22.

  11. Turn the ignition switch to LOCK (0).
  12. Jump the SCS line with the HDS.
  13. Disconnect ECM/PCM connector C (49P).
  14. Check for continuity between ETCS control relay 4P connector terminal No. 2 and ECM/PCM connector terminal C1.
    Fig 4: Checking Continuity Between ETCS Control Relay 4P Connector Terminal No. 2 And ECM/PCM Connector Terminal C1
    G07767829Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 15.

    NO  -Repair open in the wire between the ECM/PCM (CI) and the ETCS control relay, then go to step  23.

  15. Disconnect ECM/PCM connector A (49P).
  16. Check for continuity between ETCS control relay 4P connector terminal No. 3 and ECM/PCM connector terminal A21.
    Fig 5: Checking Continuity Between ETCS Control Relay 4P Connector Terminal No. 3 And ECM/PCM Connector Terminal A21
    G07767830Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step  28.

    NO  -Repair open in the wire between the ECM/PCM (A21) and the ETCS control relay, then go to step  23.

  17. Remove the ETCS control relay (A) from the under-hood fuse/relay box.
    Fig 6: Identifying ETCS Control Relay
    G07767831Courtesy of AMERICAN HONDA MOTOR CO., INC.
  18. Jump the SCS line with the HDS.
  19. Disconnect ECM/PCM connector C (49P).
  20. Check for continuity between ECM/PCM connector terminal C1 and body ground.
    Fig 7: Checking Continuity Between ECM/PCM Connector Terminal C1 And Body Ground
    G07767832Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between the ECM/PCM (C1) and the ETCS control relay, then go to step  23.

    NO  -Go to step 21.

  21. Check for continuity between ETCS control relay 4P connector terminal No. 1 and body ground.
    Fig 8: Checking Continuity Between ETCS Control Relay 4P Connector Terminal No. 1 And Body Ground
    G07767833Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Check the under-hood fuse/relay box, and replace it if needed (see REMOVAL AND INSTALLATION ), then go to step  23.

    NO  -Go to step  28.

  22. Turn the ignition switch to LOCK (0).
  23. Reconnect all connectors.
  24. Turn the ignition switch to ON (II).
  25. Reset the ECM/PCM with the HDS.
  26. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
  27. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1659 indicated? 

    YES  -Check for poor connections or loose terminals at the ETCS control relay and the ECM/PCM, then go to step  1.

    NO  -Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

  28. Reconnect all connectors.
  29. Update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ).
  30. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1659 indicated? 

    YES  -Check for poor connections or loose terminals at the ETCS control relay and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the ECM/PCM was substituted, go to step  1.

    NO  -If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ). If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

scientia non olet · About LEMON Manuals