DTC Troubleshooting
DTC Troubleshooting: P0979 (22)
DTC P0979:
Shift Solenoid Valve C Circuit (Short)
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. Test-drive the vehicle in 1st gear in D for at least 1 second, n slow down to a stop.
3. Check if DTC P0979 recurs.
Is DTC P0979 indicated?
YES -
Go to step 7.
NO -
Go to step 4.
4. Select Shift Solenoid Valve C in the Miscellaneous Test Menu, and test shift solenoid valve C with the HDS.
Is a clicking sound heard?
YES -
Go to step 5.
NO -
Go to step 7.
5. Test-drive the vehicle in 1st gear in D for at least 1 second, then slow down to a stop.
6. Monitor the OBD STATUS for P0979 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 the SHC wire for intermittent short to ground between shift solenoid valve C and the PCM. If the HDS indicates NOT COMPLETED, go to step 4 P0979 and recheck.�
7. Turn the ignition switch to LOCK (0).
8. Jump the SCS line with the HDS.
9. Disconnect PCM connector B (49P).
10. Measure the resistance between PCM connector terminal B21 and body ground.
Is there less than 12 Ohms?
YES -
Go to step 11.
NO -
Go to step 14.
11. Disconnect the shift solenoid harness connector.
12. Check for continuity between PCM connector terminal B21 and body ground.
Is there continuity?
YES -
Repair short in the wire between PCM connector terminal B21 and the shift solenoid harness connector, then go to step 20.
NO -
Go to step 13.
13. Inspect shift solenoid valve C Shift Solenoid Valve Test, Replacement, And Shift Solenoid Wire Harness Replacement.
Is shift solenoid valve C OK?
YES -
Go to step 14.
NO -
Replace shift solenoid valve C or the shift solenoid harness Shift Solenoid Valve Test, Replacement, And Shift Solenoid Wire Harness Replacement, then go to step 20.
14. Reconnect all connectors.
15. 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.
16. Start the engine in P, and wait for at least 1 second.
17. Test-drive the vehicle in 1st and 2nd gears in D. Drive in each gear for at least 1 second, then slow down to a stop.
18. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0979 indicated?
YES -
If the PCM was updated, substitute a known-good PCM Initial Inspection and Diagnostic Overview, then recheck. If the PCM was substituted, reinstall the original PCM, then go to step 1.
NO -
Go to step 19.
19. Monitor the OBD STATUS for P0979 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 P0979, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for intermittent short to body ground in the wire between shift solenoid valve C 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, reinstall the original PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 16 P0979 and recheck.
20. Reconnect all connectors.
21. Clear the DTC with the HDS.
22. Start the engine in P, and wait for at least 1 second.
23. Test-drive the vehicle in 1st and 2nd gears in D. Drive in each gear for at least 1 second, then slow down to a stop.
24. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0979 indicated?
YES -
Check for intermittent short to body ground in the wire between shift solenoid valve C and the PCM, then go to step 1.
NO -
Go to step 25.
25. Monitor the OBD STATUS for P0979 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 24 P0979, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for intermittent short to body ground in the wire between shift solenoid valve C and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 22 P0979 and recheck.