DTC Troubleshooting: P1658 (40)
DTC P1658:
 Electronic Throttle Control System (ETCS) Control Relay ON Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Do the ETCS TEST in the INSPECTION MENU with the HDS.
Is the RELAY normal?
YES -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the under-hood fuse/relay box and the ECM.■
NO -
Go to Step 3 .
  1. Turn the ignition switch OFF.
Is the ETCS control relay OK?
YES -
Go to Step 5 .
NO -
  1. Remove the battery.
  1. Disconnect ECM connector A (44P).
  1. Check for continuity between ECM connector terminal A20 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (A20) and the under-hood fuse/relay box, then go to Step 15 .
NO -
Go to Step 9 .
  1. Disconnect ECM connector C (44P).
  1. Reconnect under-hood fuse/relay box connector D (20P).
  1. Connect a battery.
  1. Turn the ignition switch ON (II).
  1. Measure voltage between ECM connector terminal C1 and body ground.
Is there battery voltage?
YES -
Repair short to power in the wire between the ECM (C1) and the under-hood fuse/relay box, then go to Step 14 .
NO -
Go to Step 20 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1658 indicated?
YES -
Check for poor connections or loose terminals at the under-hood fuse/relay box and the ECM, 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.■
  1. Reconnect all connectors.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1658 indicated?
YES -
Check for poor connections or loose terminals at the under-hood fuse/relay box and the ECM. If the ECM was updated, substitute a known-good ECM, then recheck. If the ECM was substituted, go to Step 1 .
NO -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■