P0979
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. Clear the DTC with the HDS.
2. Test-drive the vehicle in 1st gear in the D position for more than 1 second.
3. Check that DTC P0979 recurs.
Is DTC P0979 indicated?
YES - Go to step 7.
NO - Go to step 4.
4. Choose Shift Solenoid C in Miscellaneous Test Menu, and test the 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 3rd gear in the D3 position for more than 1 second.
6. Monitor the OBD status for P0979 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the result indicate FAILED?
YES - Go to step 7.
NO - Intermittent failure, the system is OK at this time. Check for an intermittent short to ground in the wire between shift solenoid valve C and the PCM. If the HDS indicates NOT COMPLETED, return to step 4 and recheck.
7. Turn the ignition switch OFF.
8. Jump the SCS line with the HDS.
9. Disconnect PCM connectors B (44P) and C (44P).
10. Measure resistance between PCM connector terminals B20 and C40.
Is there less than 12 ohms?
YES - Go to step 11.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck for DTC P0979. If the symptom/indication goes away with a known-good PCM, replace the original PCM, then go to step 14.
11. Disconnect the shift solenoid harness connector.
12. Check for continuity between PCM connector terminals B20 and C40.
Is there continuity?
YES - Repair short to ground in the wire between PCM connector terminal B20 and the shift solenoid harness connector, then go to step 14.
NO - Go to step 13.
13. Inspect shift solenoid valve C.
Is shift solenoid valve C OK?
YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck for DTC P0979. If the symptom/indication goes away with a known-good PCM, replace the original PCM, then go to step 14.
NO - Replace shift solenoid valve C or shift solenoid harness, then go to step 14.
14. Clear the DTC with the HDS.
15. Test-drive the vehicle in 3rd gear in the D3 position for more than 1 second.
16. Monitor the OBD status for P0979 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the result indicate PASSED?
YES - Troubleshooting is complete.
NO - If the PCM was updated and the screen indicates FAILED, substitute a known-good PCM, then return to step 14. If the PCM was substituted and the screen indicates FAILED, return to step 1 and recheck. If the screen indicates NOT COMPLETED, return to step 15.