DTC Troubleshooting
DTC Troubleshooting: P0873 (27-4)
DTC P0873:
Transmission Fluid Pressure Switch C (4th Clutch) Circuit High
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.
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
4. Test-drive the vehicle in 4th gear in D, and verify with the HDS in the A/T Data List that the Shift Control indicates 4th.
5. Check the 4th Pressure Switch signal with the HDS in the A/T Data List.
Is the 4th Pressure Switch ON?
YES -
Go to step 6.
NO -
Go to step 8.
6. Test-drive the vehicle in 4th gear in D for at least 2 seconds. Slow down, and stop the wheels.
7. Monitor the OBD STATUS for P0873 in the DTCs MENU with the HDS.
Does the HDS indicate FAILED?
YES -
Go to step 8.
NO -
If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals between the transmission fluid pressure switch C (4th clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 6.
8. Turn the ignition switch to LOCK (0).
9. Disconnect the transmission fluid pressure switch C (4th clutch) connector.
10. Connect a jumper wire between the transmission fluid pressure switch C (4th clutch) connector terminal and body ground.
11. Turn the ignition switch to ON (II).
12. Check the 4th Pressure Switch signal with the HDS in the A/T Data List.
Is the 4th Pressure Switch ON?
YES -
Go to step 13.
NO -
Go to step 16.
13. Reconnect the transmission fluid pressure switch C (4th clutch) connector.
14. Clear the DTC with the HDS.
15. Measure the 4th clutch pressure A/T Pressure Test.
Is the 4th clutch pressure within the service limits?
YES -
Replace the transmission fluid pressure switch C (4th clutch) Transmission Fluid Pressure Switch C (4th Clutch) Replacement, then go to step 26.
NO -
Repair shift valves A, B, C, and D, and related hydraulic circuit, or replace the transmission, then go to step 29.
16. Turn the ignition switch to LOCK (0).
17. Jump the SCS line with the HDS.
18. Disconnect PCM connector C (49P).
19. Check for continuity between PCM connector terminal C37 and the transmission fluid pressure switch C (4th clutch) connector terminal.
Is there continuity?
YES -
Go to step 20.
NO -
Repair an open in the wire between PCM connector terminal C37 and the transmission fluid pressure switch C (4th clutch), then go to step 26.
20. Reconnect all connectors.
21. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
22. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
23. 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.
24. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0873 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 25.
25. Monitor the OBD STATUS for P0873 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 24, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals 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 23.
26. Reconnect all connectors.
27. Turn the ignition switch to ON (II).
28. Clear the DTC with the HDS.
29. Start the engine in P, and warm it up to normal operating temperature (the radiator fan comes on).
30. 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.
31. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0873 indicated?
YES -
Check for poor connections or loose terminals between the transmission fluid pressure switch C (4th clutch) and the PCM, then go to step 1.
NO -
Go to step 32.
32. Monitor the OBD STATUS for P0873 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 31, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals 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 30.