DTC Troubleshooting
DTC Troubleshooting: P0843 (25)
DTC P0843:
Transmission Fluid Pressure Switch A (2nd Clutch) 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 The A/T System.
- This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
K24Z6 Engine
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. Shift into the 2 position while pressing the brake pedal, and check 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. Drive the vehicle in 2nd gear in D for at least 2 seconds, then slow down to a stop.
6. Monitor the OBD STATUS for P0843 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 for poor connections and loose terminals at transmission fluid pressure switch A (2nd clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 5 P0843 and recheck.�
7. Turn the ignition switch to LOCK (0).
8. Disconnect the transmission fluid pressure switch A (2nd clutch) connector.
9. Turn the ignition switch to ON (II).
10. Measure the voltage between the transmission fluid pressure switch A (2nd clutch) connector terminal and body ground.
Is there about 5 V?
YES -
Replace transmission fluid pressure switch A (2nd clutch) Transmission Fluid Pressure Switch A (2nd 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 B (49P).
14. Check for continuity between PCM connector terminal B8 and the transmission fluid pressure switch A (2nd clutch) connector terminal.
Is there continuity?
YES -
Check for poor connections and loose terminals at transmission fluid pressure switch A (2nd clutch) and the PCM. If the connections are OK, go to step 15.
NO -
Repair open in the wire between PCM connector terminal B8 and transmission fluid pressure switch A (2nd clutch), then go to step 20.
15. Reconnect all connectors.
16. Update the A/T software in the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM Initial Inspection and Diagnostic Overview.
17. Drive the vehicle in 2nd gear in D for at least 2 seconds. Then accelerate until the transmission upshifts into 4th gear, and drive for at least 2 seconds. Slow down and stop the wheels.
18. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0843 indicated?
YES -
If the PCM was updated, substitute a known-good PCM Initial Inspection and Diagnostic Overview, then recheck. If the PCM was substituted, go to step 1.
NO -
Go to step 19.
19. Monitor the OBD STATUS for P0843 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 on step 18 P0843, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for poor connections and loose terminals at transmission fluid pressure switch A (2nd clutch) and the PCM. If the PCM was updated, substitute a known-good PCM Initial Inspection and Diagnostic Overview, then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 17 P0843 and recheck.
20. Reconnect all connectors.
21. Clear the DTC with the HDS.
22. Drive the vehicle in 2nd gear in D for at least 2 seconds. Then accelerate until the transmission upshifts into 4th gear, and drive for at least 2 seconds. Slow down and stop the wheels.
23. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0843 indicated?
YES -
Check for poor connections and loose terminals at transmission fluid pressure switch A (2nd clutch) and the PCM, then go to step 1.
NO -
Go to step 24.
24. Monitor the OBD STATUS for P0843 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 on step 23 P0843, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for poor connections and loose terminals at transmission fluid pressure switch A (2nd clutch) and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 22 P0843 and recheck.