DTC Troubleshooting
DTC Troubleshooting: P0848 (26-4)
DTC P0848:
Open in Transmission Fluid Pressure Switch B (3rd Clutch) Circuit, or Transmission Fluid Pressure Switch B (3rd Clutch) Stuck OFF
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review 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, and warm it up to normal operating temperature (the radiator fan comes on).
4. Test-drive the vehicle in 3rd gear in D, and verify with the HDS in the A/T Data List that the Shift Control indicates 3rd.
5. Check the 3rd Pressure Switch signal with the HDS in the A/T Data List.
Is the 3rd Pressure Switch ON?
YES -
Go to step 6.
NO -
Go to step 8.
6. Test-drive the vehicle in 3rd gear in D for at least 2 seconds. Slow down, and stop the wheels.
7. Monitor the OBD STATUS for P0848 in the DTCs MENU with the HDS.
Does the HDS indicate FAILED?
YES -
Go to step 9.
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 B (3rd clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 6.
8. Measure the 3rd clutch pressure A/T Pressure Test.
Is the 3rd clutch pressure within the service limits?
YES -
Go to step 9.
NO -
Repair shift valves A, B, and C, and related hydraulic circuit, or replace the transmission, then go to step 25.
9. Turn the ignition switch to LOCK (0).
10. Disconnect the transmission fluid pressure switch B (3rd clutch) connector.
11. Turn the ignition switch to ON (II).
12. Measure the voltage between the transmission fluid pressure switch B (3rd clutch) connector terminal and body ground.
Is there about 5 V?
YES -
Replace the transmission fluid pressure switch B (3rd clutch) Transmission Fluid Pressure Switch B (3rd Clutch) Replacement, then go to step 22.
NO -
Go to step 13.
13. Turn the ignition switch to LOCK (0).
14. Jump the SCS line with the HDS.
15. Disconnect PCM connector C (49P).
16. Check for continuity between PCM connector terminal C38 and the transmission fluid pressure switch B (3rd clutch) connector terminal.
Is there continuity?
YES -
Go to step 17.
NO -
Repair an open in the wire between PCM connector terminal C38 and the transmission fluid pressure switch B (3rd clutch), then go to step 22.
17. Reconnect all connectors.
18. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
19. Test-drive the vehicle in 3rd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 4th gear, and drive for at least 2 seconds. Slow down, and stop the wheels.
20. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0848 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 21.
21. Monitor the OBD STATUS for P0848 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 in step 20, 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 B (3rd 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 19.
22. Reconnect all connectors.
23. Turn the ignition switch to ON (II).
24. Clear the DTC with the HDS.
25. Test-drive the vehicle in 3rd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 4th 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 P0848 indicated?
YES -
Check for poor connections or loose terminals between the transmission fluid pressure switch B (3rd clutch) and the PCM, then go to step 1.
NO -
Go to step 27.
27. Monitor the OBD STATUS for P0848 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 poor connections or loose terminals between the transmission fluid pressure switch B (3rd clutch) and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 25.