Automatic Transmission
DTC P0873: Open in 4th Clutch Transmission Fluid Pressure Switch Circuit, or 4th Clutch Transmission Fluid Pressure Switch Stuck OFFNOTE:
^ Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.
^ 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 ON (II).
2. Clear the DTC with the HDS.
3. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
4. Drive the vehicle in 4th gear in the D position for at least 2 seconds, then drive in 5th gear for at least 2 seconds.
5. Check the 4th PRESSURE SWITCH in the DATA LIST with the HDS.
Is the 4th PRESSURE SWITCH ON?
YES - Go to step 6.
NO - Go to step 8.
6. Drive the vehicle in 4th gear in the D position for at least 2 seconds, then drive in 5th gear for at least 2 seconds.
7. Monitor the OBD STATUS for P0873 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES - Go to step 8.
NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for intermittent short to body ground in the wire between the 4th clutch transmission fluid pressure switch and the PCM. If the screen indicates NOT COMPLETED, go to step 5.
8. Turn the ignition switch OFF.
9. Disconnect the 4th clutch transmission fluid pressure switch connector.
10. Turn the ignition switch ON (II).
11. Measure the voltage between the 4th clutch transmission fluid pressure switch connector terminal and body ground.
Is there about 5 V?
YES - Replace the 4th clutch transmission fluid pressure switch, then go to step 16.
NO - Go to step 12.
12. Turn the ignition switch OFF.
13. Jump the SCS line with the HDS.
14. Disconnect PCM connector C (44P).
15. Check for continuity between PCM connector terminal C16 and the 4th clutch transmission fluid pressure switch connector terminal.
Is there continuity?
YES - Go to step 23.
NO - Repair open in the wire between PCM connector terminal C16 and the 4th clutch transmission fluid pressure switch, then go to step 16.
16. Reconnect all connectors.
17. Turn the ignition switch ON (II).
18. Clear the DTC with the HDS.
19. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
20. Drive the vehicle in 4th gear in the D position, for at least 2 seconds, then drive in 5th gear for at least 2 seconds.
21. Check for DTCs with the HDS.
Is DTC P0873 indicated?
YES - Check for poor connections or loose terminals between the 4th transmission fluid pressure switch and the PCM, then go to step 1.
NO - Go to step 22.
22. Monitor the OBD STATUS for P0873 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated in step 21, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals between the 4th transmission fluid pressure switch and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 19.
23. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
24. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
25. Drive the vehicle in 4th gear in the D position, for at least 2 seconds, then drive in 5th gear for at least 2 seconds.
26. Check for DTCs with the HDS.
Is DTC P0873 indicated?
YES - Check for poor connections or loose terminals between the 4th clutch transmission fluid pressure switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 24. If the PCM was substituted, go to step 1.
NO - Go to step 27.
27. Monitor the OBD STATUS for P0873 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other DTCs were indicated in step 26, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals between the 4th clutch transmission fluid pressure switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 24. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 24.