2011 Acura TL BaseFACTORY OEM SERVICE PROCEDURE

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), or press the engine start/stop button to select the ON mode
  2. Clear the DTC with the HDS
  3. Check for Pending or Confirmed DTCs with the HDS

    4. 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 PCM

  4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
  5. Check the No 18 DBW (THROTTLE ACTUATOR CONTROL) (15 A) fuse in the under-hood fuse/relay box

    6. 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 From Under-Hood Fuse/Relay Box
    G05987478Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Test the ETCS control relay (see POWER RELAY TEST )

    8. 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), or press the engine start/stop button to select the ON mode
  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
    G05987479Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 10

    NO  -Replace the under-hood fuse/relay box (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
    G05987480Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 11

    NO  -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ), then go to step  22

  11. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
  12. Jump the SCS line with the HDS
  13. Disconnect PCM connector C (49P)
  14. Check for continuity between ETCS control relay 4P connector terminal No 2 and PCM connector terminal C4
    Fig 4: Checking Continuity Between ETCS Control Relay 4P Connector Terminal No 2 And PCM Connector Terminal C4
    G05987481Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 15

    NO  -Repair open in the wire between the PCM (C4) and the ETCS control relay, then go to step  23

  15. Disconnect PCM connector A (49P).
  16. Check for continuity between ETCS control relay 4P connector terminal No 3 and PCM connector terminal A29
    Fig 5: Checking Continuity Between ETCS Control Relay 4P Connector Terminal No 3 And PCM Connector Terminal A29
    G05987482Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step  28

    NO  -Repair open in the wire between the PCM (A29) 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 From Under-Hood Fuse/Relay Box
    G05987483Courtesy of AMERICAN HONDA MOTOR CO., INC.
  18. Jump the SCS line with the HDS
  19. Disconnect PCM connector C (49P)
  20. Check for continuity between PCM connector terminal C4 and body ground
    Fig 7: Checking Continuity Between PCM Connector Terminal C4 And Body Ground
    G05987484Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between the PCM (C4) 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
    G05987485Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ), then go to step  23

    NO  -Go to step  28

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

    28. Is DTC P1659 indicated? 

    YES  -Check for poor connections or loose terminals at the ETCS control relay and the 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 PCM if it does not have the latest software (see ECM/PCM UPDATE ), or substitute a known-good 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 PCM If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ), then recheck If the PCM was substituted, go to step  1

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

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.