Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P1658: ETCS Control Relay ON Malfunction
- Turn the ignition switch to ON (II).
- 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 electronic throttle control system (ETCS) control relay and the PCM.
NO - Go to step 3.
- Turn the ignition switch to LOCK (0).
- Remove the electronic throttle control system (ETCS) control relay (A) from the passenger's under-dash fuse/relay box.
- 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 6.
NO - Replace the electronic throttle control system (ETCS) control relay, then go to step 13.
- Jump the SCS line with the HDS.
- Disconnect PCM connector A (49P).
- Check for continuity between PCM connector terminal A29 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Repair short in the wire between the PCM (A29) and the electronic throttle control system (ETCS) control relay, then go to step 13.
NO - Go to step 9.
- Disconnect PCM connector C (49P).
- Turn the ignition switch to ON (II).
- Measure the voltage between PCM connector terminal C4 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES - Repair short to power in the wire between the PCM (C4) and the electronic throttle control system (ETCS) control relay, then go to step 12.
NO - Go to step 18.
- Turn the ignition switch to LOCK (0).
- Reconnect all connectors.
- Turn the ignition switch to ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1658 indicated?
YES - Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM, then go to step 1.
NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .
- Turn the ignition switch to LOCK (0).
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1658 indicated?
YES - Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE 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 PCM REPLACEMENT ). If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .
NO RELATED
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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.