DTC Troubleshooting: P0642 (133)
DTC P0642:
 Sensor Reference Voltage A Circuit Low Voltage
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0642 indicated?
YES -
Go to Step 4 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the APP sensor and the ECM.■
  1. Turn the ignition switch OFF.
  1. Disconnect the APP sensor 6P connector.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0642 indicated?
YES -
Go to Step 9 .
NO -
Go to Step 12 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 2 (58P).
  1. Check for continuity between body ground and ECM connector No. 2 terminals No. 14, No. 15 individually.
Is there continuity?
YES -
Repair short in the wire between the APP sensor and ECM connector No. 2 terminal No. 14 (No. 15) * , then go to Step 14 .
NO -
Go to Step 18 .
*: APSBVCC line
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors.
  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 P0642 indicated?
YES -
Check for poor connections or loose terminals at the APP sensor 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 P0642 indicated?
YES -
Check for poor connections or loose terminals at the APP sensor 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 were indicated in Step 13 , go to the indicated DTC's troubleshooting.■