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 to ON (II).
  1. 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 under-hood fuse/relay box and the ECM.■
NO -
Go to Step 3 .
  1. Turn the ignition switch to LOCK (0).
Is the relay OK?
YES -
Go to Step 5 .
NO -
  1. Jump the SCS line with the HDS.
  1. Disconnect under-hood fuse/relay box (white) connector D (20P).
  1. Disconnect ECM connector A (49P).
  1. Check for continuity between ECM connector terminal A21 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (A21) and the under-hood fuse/relay box, then go to Step 15 .
NO -
Go to Step 9 .
  1. Disconnect ECM connector C (49P).
  1. Reconnect under-hood fuse/relay box (white) connector D (20P).
  1. Turn the ignition switch to ON (II).
  1. Measure the 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 13 .
NO -
Go to Step 19 .
  1. Turn the ignition switch to LOCK (0).
  1. Reconnect all connectors.
  1. Turn the ignition switch to 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.■