Automatic Transmission
DTC P0979: Short in Shift Solenoid Valve C CircuitNOTE:
^ 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 to ON (II).
2. Clear the DTC with the HDS.
3. Test-drive the vehicle in 1st gear with the shift lever in M for at least 1 second.
4. Check for DTCs with the HDS.
Is DTC P0979 indicated?
YES - Go to step 8.
NO - Go to step 5.
5. Select Shift Solenoid C in the Miscellaneous Test Menu, and test shift solenoid valve C with the HDS.
Is a clicking sound heard?
YES - Go to step 6.
NO - Go to step 8.
6. Test-drive the vehicle in 1st gear with the shift lever in M for at least 1 second.
7. Monitor the OBD STATUS for P0979 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 shift solenoid valve C and the PCM. If the screen indicates NOT COMPLETED, go to step 5.
8. Turn the ignition switch to LOCK (0).
9. Jump the SCS line with the HDS.
10. Disconnect PCM connectors A (31P) and C (22P).
11. Measure the resistance between PCM connector terminals C2 and A9.
Is there less than 12 ohms ?
YES - Go to step 12.
NO - Go to step 22.
12. Disconnect the shift solenoid harness connector at the transmission housing.
13. Check for continuity between PCM connector terminals C2 and A9.
Is there continuity?
YES - Repair short to body ground in the wire between PCM connector terminal C2 and the shift solenoid harness connector, then go to step 15.
NO - Go to step 14.
14. Inspect shift solenoid valve C and the shift solenoid harness.
Are shift solenoid valve C and the harness OK?
YES - Go to step 22.
NO - Replace shift solenoid valve C or the shift solenoid harness, then go to step 15.
15. Reconnect all connectors.
16. Turn the ignition switch to ON (II).
17. Clear the DTC with the HDS.
18. Start the engine with the shift lever in P, and wait for at least 1 second.
19. Drive the vehicle in 1st gear with the shift lever in M for at least 1 second.
20. Check for 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 21.
21. Monitor the OBD STATUS for P0979 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated in step 20, go to the indicated DTC's troubleshooting.
NO - If the screen 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 screen indicates NOT COMPLETED, go to step 18.
22. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
23. Start the engine with the shift lever in P, and wait for at least 1 second.
24. Drive the vehicle in 1st gear with the shift lever in M for at least 1 second.
25. Check for 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. If the PCM was updated, substitute a known-good PCM, then go to step 23. If the PCM was substituted, go to step 1.
NO - Go to step 26.
26. Monitor the OBD STATUS for P0979 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 25, go to the indicated DTC's troubleshooting.
NO - If the screen 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, then go to step 23. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 23.