2012 Acura TL BaseFACTORY OEM SERVICE PROCEDURE

DTC P1658: ETCS Control Relay ON 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. Do the ETCS TEST in the INSPECTION MENU with the HDS.

    Is the RELAY circuit OK? 

    YES  - 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. ■

    NO  - Go to step 3.

  3. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  4. Remove the ETCS control relay (A) from the under-hood fuse/relay box.
    Fig 1: Identifying ETCS Control Relay
    G08069613Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. Test the ETCS control relay (see POWER RELAY TEST ).

    Is the ETCS control relay OK? 

    YES  - Go to step 6.

    NO  - Replace the ETCS control relay, then go to step  13.

  6. Jump the SCS line with the HDS.
  7. Disconnect ECM/PCM connector A (49P).
  8. Check for continuity between ECM/PCM connector terminal A29 and body ground.
    Fig 2: Checking Continuity Between ECM/PCM Connector Terminal A29 And Body Ground
    G08069614Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the ECM/PCM (A29) and the ETCS control relay, then go to step  13.

    NO  - Go to step 9.

  9. Disconnect ECM/PCM connector C (49P).
  10. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  11. Measure the voltage between ECM/PCM connector terminal C4 and body ground.
    Fig 3: Measuring Voltage Between ECM/PCM Connector Terminal C4 And Body Ground
    G08069615Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Repair short to power in the wire between the ECM/PCM (C4) and the ETCS control relay, then go to step 12.

    NO  - Go to step  18.

  12. Turn the ignition switch to LOCK(0), or press the engine start/stop button to select the OFF mode.
  13. Reconnect ail connectors.
  14. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  15. Reset the ECM/PCM with the HDS.
  16. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
  17. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1658 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. ■

  18. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  19. Reconnect all connectors.
  20. 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 ).
  21. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1658 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. ■

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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.

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