DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P1658

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 How to Troubleshoot the Fuel And Emissions Systems.


1. Problem verification:

-1. Turn the ignition switch to ON (II).

-2. Do the ETCS TEST 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 PCM.
-NO- The failure is duplicated. Go to step 2.

2. ETCS control relay test:

-1. Turn the ignition switch to LOCK (0).

-2. Remove the ETCS control relay (A) from the under-dash fuse/relay box.






-3. Test the ETCS control relay Testing and Inspection.

Is the ETCS control relay OK?
-YES- The ETCS control relay is OK. Go to step 3.
-NO- Replace the ETCS control relay, then do the repair verification.

3. Shorted wire check (ETCS RLY CL- line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.






-4. Check for continuity between test points 1 and 2.










Is there continuity?
-YES- Repair a short in the ETCS RLY CL- wire between the PCM (A48) and the throttle body, then do the repair verification.
-NO- The ETCS RLY CL- wire is OK. Go to step 4.

4. Shorted wire check (VBETCS line to power):

-1. Disconnect the following connector.






-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.










Is there battery voltage?
-YES- Repair a short to power in the VBETCS wire between the PCM (C1) and the ETCS control relay, then do the repair verification.
-NO- The VBETCS wire is OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

Repair verification:

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the PCM with the HDS How to Troubleshoot the Fuel And Emissions Systems.

-5. Do the PCM idle learn procedure PCM Idle Learn Procedure.

-6. 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 PCM. If the PCM was updated, substitute a known-good PCM Service and Repair, then recheck. If the PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.