( TF09E1PK77100090979FAAT00 )

DTC Troubleshooting: P0979 (22)

DTC P0979:

Shift Solenoid Valve C (Short)

NOTE:

Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, 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.

Clear the DTC with the HDS.

Start the engine, and test-drive the vehicle:
- Seven-position transmission: Drive the vehicle in D3, and let the transmission shift through all three gears. Drive the vehicle in 3rd gear for at least 1 second, then slow down to a stop.
- Five-position transmission: Drive the vehicle in 1st thru 3rd gears in the sequential shift mode in S. Drive the vehicle in 3rd gear for at least 1 second, then slow down to a stop.

Check that DTC P0979 recurs.

Is DTC P0979 indicated?

YES	-	Go to Step 7 .
NO	-	Go to Step 4 .

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 5 .
NO	-	Go to Step 7 .

Start the engine, and test-drive the vehicle:
- Seven-position transmission: Drive the vehicle in D3, and let the transmission shift through all three gears, then slow down to a stop. Shift into P, and wait for at least 1 second.
- Five-position transmission: Drive the vehicle in 1st thru 3rd gears in the sequential shift mode in S, then slow down to a stop. Shift into P, and wait for at least 1 second.

Monitor the OBD status for P0979 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate FAILED?

YES	-	Go to Step 7 .
NO	-	Intermittent failure, the system is OK at this time. Check the SH C wire for an intermittent short to ground between shift solenoid valve C and the PCM. If the HDS indicates NOT COMPLETED, return to Step 4 and recheck.

Turn the ignition switch to LOCK (0).

Jump the SCS line with the HDS.

Disconnect PCM connectors B (49P) and C (49P).

Measure the resistance between PCM connector terminals B21 and C44 or C48.

Is there less than 12 Ω?

YES	-	Go to Step 11 .
NO	-	Go to Step 17 .

Disconnect the shift solenoid harness connector.

Check for continuity between PCM connector terminals B21 and C44 or C48.

Is there continuity?

YES	-	Repair short in the wire between PCM connector terminal B21 and the shift solenoid harness connector, then go to Step 22 .
NO	-	Go to Step 13 .

Inspect shift solenoid valve C.

Is shift solenoid valve C OK?

YES	-	Go to Step 14 .
NO	-	Replace shift solenoid valve C or the shift solenoid harness, then go to Step 22 .

Disconnect PCM connector A (49P).

Turn the ignition switch to ON (II).

Measure the voltage between PCM connector terminals A1 and C44 or C48.

Is there battery voltage?

YES	-	Go to Step 17 .
NO	-	Check for a blown No. 7 (10 A) fuse in the under-hood fuse/relay box. If the fuse is OK, repair open or short in the wire between PCM connector terminal A1 and the under-hood fuse/relay box, then go to Step 22 .

Connect PCM connectors.

Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.

Start the engine, and test-drive the vehicle:
- Seven-position transmission: Drive the vehicle in D3, and let the transmission shift through all three gears, then slow down to a stop. Shift into P, and wait for at least 1 second.
- Five-position transmission: Drive the vehicle in 1st thru 3rd gears in the sequential shift mode in S, then slow down to a stop. Shift into P, and wait for at least 1 second.

Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0979 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 .

Monitor the OBD status for P0979 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS 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 on Step 20 , go to the indicated DTC's troubleshooting.■
NO	-	Check for an intermittent short in the wire between shift solenoid valve C 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, return to Step 19 and recheck.

Reconnect all connectors.

Clear the DTC with the HDS.

Start the engine, and test-drive the vehicle:
- Seven-position transmission: Drive the vehicle in D3, and let the transmission shift through all three gears, then slow down to a stop. Shift into P, and wait for at least 1 second.
- Five-position transmission: Drive the vehicle in 1st thru 3rd gears in the sequential shift mode in S, then slow down to a stop. Shift into P, and wait for at least 1 second.

Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0979 indicated?

YES	-	Check for an intermittent short in the wire between shift solenoid valve C and the PCM, then go to Step 1 .
NO	-	Go to Step 26 .

Monitor the OBD status for P0979 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate PASSED?

YES	-	Troubleshooting is complete. If any other DTCs were indicated on Step 25 , go to the indicated DTC's troubleshooting.■
NO	-	Check for an intermittent short in the wire between shift solenoid valve C and the PCM, then go to Step 1 . If the HDS indicates NOT COMPLETED, return to Step 24 and recheck.