DTC Troubleshooting

DTC Troubleshooting: P0843 (25)

DTC P0843: 2nd Clutch Transmission Fluid Pressure Switch Circuit (Open or Stuck OFF)

NOTE:

- Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information. How to Troubleshoot A/T Systems

- This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

1. Clear the DTC with the HDS.

2. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).

3. Move the shift lever into S while pressing the brake pedal, upshift to 2nd gear by pulling the paddle shifter + (upshift switch), and verify with the HDS in the A/T data list that the Shift Command indicates 2nd.

4. Check the 2nd Pressure Switch signal with the HDS in the A/T data list.

Is the 2nd Pressure Switch ON?
YES - Go to step 5.

NO - Go to step 7.


5. Test-drive the vehicle in 2nd gear with the shift lever in S for at least 2 seconds, then slow down to a stop.

6. Monitor the OBD STATUS for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate FAILED?
YES - Go to step 8.

NO - Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals at the 2nd clutch transmission fluid pressure switch and the PCM. If the HDS indicates NOT COMPLETED, return to step 5 and recheck.


7. Measure the 2nd clutch pressure. A/T Pressure Test

Is the 2nd clutch pressure within the service limits?
YES - Go to step 8.

NO - Repair shift valves A and C, and related hydraulic circuit, or replace the transmission, then go to step 22.


8. Turn the ignition switch to LOCK (0).

9. Disconnect the 2nd clutch transmission fluid pressure switch connector.

10. Turn the ignition switch to ON (II).

11. Measure the voltage between the 2nd clutch transmission fluid pressure switch connector terminal and body ground.

Is there about 5 V?
YES - Replace the 2nd clutch transmission fluid pressure switch, 2nd Clutch Transmission Fluid Pressure Switch Replacement then go to step 21.

NO - Go to step 12.






12. Turn the ignition switch to LOCK (0).

13. Jump the SCS line with the HDS.

14. Disconnect PCM connector B (44P).

15. Check for continuity between PCM connector terminal B8 and the 2nd clutch transmission fluid pressure switch connector terminal.

Is there continuity?
YES - Check for poor connections and loose terminals at the 2nd clutch transmission fluid pressure switch and the PCM. If the connections are OK, go to step 16.

NO - Repair open in the wire between PCM connector terminal B8 and the 2nd clutch transmission fluid pressure switch, then go to step 21.






16. Reconnect all connectors.

17. Update the A/T software in the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. How to Troubleshoot A/T Systems

18. Test-drive the vehicle in 2nd gear with the shift lever in S for at least 2 seconds, then upshift to 4th gear, and drive in 4th gear for at least 2 seconds. Slow down and stop the wheels.

19. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0843 indicated?
YES - If the PCM was updated, substitute a known-good PCM, How to Troubleshoot A/T Systems then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 20.


20. Monitor the OBD STATUS for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

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 DTCs were indicated on step 19, go to the indicated DTC's troubleshooting.

NO - Check for poor connections and loose terminals at the 2nd clutch transmission fluid pressure switch and the PCM. If the PCM was updated, substitute a known-good PCM, How to Troubleshoot A/T Systems then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, return to step 18 and recheck.


21. Reconnect all connectors.

22. Clear the DTC with the HDS.

23. Test-drive the vehicle in 2nd gear with the shift lever in S for at least 2 seconds, then upshift to 4th gear, and drive in 4th gear for at least 2 seconds. Slow down and stop the wheels.

24. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0843 indicated?
YES - Check for poor connections and loose terminals at the 2nd clutch transmission fluid pressure switch and the PCM, then go to step 1.

NO - Go to step 25.


25. Monitor the OBD STATUS for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated on step 24, go to the indicated DTC's troubleshooting.

NO - Check for poor connections and loose terminals at the 2nd clutch transmission fluid pressure switch and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, return to step 23 and recheck.