DTC Troubleshooting
DTC Troubleshooting: P0872 (27-3)
DTC P0872:
Transmission Fluid Pressure Switch C (4th Clutch) Circuit Low
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. Clear the DTC with the HDS.
3. Check the 4th Pressure Switch signal with the HDS in the A/T Data List when not in 4th gear.
Is the 4th Pressure Switch OFF?
YES -
Go to step 4.
NO -
Go to step 7.
4. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
5. Test-drive the vehicle in 5th gear in D for at least 2 seconds. Slow down, and stop the wheels.
6. Monitor the OBD STATUS for P0872 in the DTCs MENU with the HDS.
Does the HDS indicate FAILED?
YES -
Go to step 7.
NO -
If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check the OP4SW wire for intermittent short to body ground between the transmission fluid pressure switch C (4th clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 5.
7. Turn the ignition switch to LOCK (0).
8. Disconnect the transmission fluid pressure switch C (4th clutch) connector.
9. Turn the ignition switch to ON (II).
10. Check the 4th Pressure Switch signal with the HDS in the A/T Data List.
Is the 4th Pressure Switch OFF?
YES -
Replace the transmission fluid pressure switch C (4th clutch) Transmission Fluid Pressure Switch C (4th Clutch) Replacement, then go to step 21.
NO -
Go to step 11.
11. Turn the ignition switch to LOCK (0).
12. Jump the SCS line with the HDS.
13. Disconnect PCM connector C (49P).
14. Check for continuity between PCM connector terminal C37 and body ground.
Is there continuity?
YES -
Repair a short to body ground in the wire between PCM connector terminal C37 and the transmission fluid pressure switch C (4th clutch), then go to step 21.
NO -
Go to step 15.
15. Reconnect all connectors.
16. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
17. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
18. Test-drive the vehicle in 4th gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 5th gear, and drive for at least 2 seconds. Slow down and stop the wheels.
19. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0872 indicated?
YES -
If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.
NO -
Go to step 20.
20. Monitor the OBD STATUS for P0872 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 PCM Replacement (Except FFV Model). If any other Pending or Confirmed DTCs were indicated in step 19, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for intermittent short to body ground in the wire between the transmission fluid pressure switch C (4th clutch) and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 18.
21. Reconnect all connectors.
22. Turn the ignition switch to ON (II).
23. Clear the DTC with the HDS.
24. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
25. Test-drive the vehicle in 4th gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 5th gear, and drive for at least 2 seconds. Slow down and stop the wheels.
26. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0872 indicated?
YES -
Check for intermittent short to body ground in the wire between the transmission fluid pressure switch C (4th clutch) and the PCM, then go to step 1.
NO -
Go to step 27.
27. Monitor the OBD STATUS for P0872 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 26, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for intermittent short to body ground in the wire between the transmission fluid pressure switch C (4th clutch) and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 25.