DTC Troubleshooting: P0643 (133)
DTC P0643:
 Sensor Reference Voltage A Circuit High 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 P0643 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, and wait 2 minutes.
  1. Disconnect ECM connector No. 2 (58P).
  1. Turn the ignition switch ON (II).
  1. Measure voltage between body ground and ECM connector No. 2 terminals No. 14, No. 15 individually.
Is there battery voltage?
YES -
Repair short to power in the wire between the APP sensor and ECM connector No. 2 terminal No. 14 (No. 15) * , then go to Step 12 .
NO -
Go to Step 8 .
*: APSBVCC line
  1. Turn the ignition switch OFF.
  1. Disconnect the APP sensor 6P connector.