DTC Troubleshooting
DTC Troubleshooting: P0812 (65-2)
DTC P0812:
Open in Transmission Range Switch ATPR Switch Circuit
NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review the General Troubleshooting Information How to Troubleshoot the A/T System.
- This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
1. Turn the ignition switch to ON (II).
2. Shift to R, and verify the A/T R Switch signal with the HDS in the A/T Data List.
Is the A/T R Switch ON?
YES -
Intermittent failure, the system is OK at this time.
NO -
Go to step 3.
3. Turn the ignition switch to LOCK (0).
4. Disconnect the transmission range switch connector.
5. Connect a jumper wire between transmission range switch connector terminal No. 8 and body ground.
6. Turn the ignition switch to ON (II).
7. Check the A/T R Switch signal with the HDS.
Is the A/T R Switch ON?
YES -
Replace the transmission range switch Service and Repair, then go to step 12.
NO -
Go to step 8.
8. Turn the ignition switch to LOCK (0).
9. Jump the SCS line with the HDS.
10. Disconnect PCM connector C (49P).
11. Check for continuity between PCM connector terminal C25 and body ground.
Is there continuity?
YES -
Go to step 18.
NO -
Repair an open in the wire between PCM connector terminal C25 and the transmission range switch, then go to step 12.
12. Reconnect all connectors.
13. Turn the ignition switch to ON (II).
14. Clear the DTC with the HDS.
15. Test-drive the vehicle in R at speeds below 3 mph(5 km/h) for at least 2 seconds, then increase the speed and test-drive at speeds over 3 mph(5 km/h) for at least 2 seconds. Slow down, and stop the wheels.
16. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0812 indicated?
YES -
Check for poor connections or loose terminals between the transmission range switch and the PCM, then go to step 1.
NO -
Go to step 17.
17. Monitor the OBD STATUS for P0812 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 16, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals between the transmission range switch and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 15.
18. Reconnect all connectors.
19. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
20. Test-drive the vehicle in R at speeds below 3 mph(5 km/h) for at least 2 seconds, then increase the speed and test-drive at speeds over 3 mph(5 km/h) for at least 2 seconds. Slow down, and stop the wheels.
21. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0812 indicated?
YES -
Check for poor connections or loose terminals between the transmission range switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 20. If the PCM was substituted, go to step 1.
NO -
Go to step 22.
22. Monitor the OBD STATUS for P0812 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 21, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals between the transmission range switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 20. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 20.