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DTC Troubleshooting: P0979 (22)

DTC P0979:
 Shift Solenoid Valve C (Short)
NOTE:
  1. Clear the DTC with the HDS.
  1. 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.
  1. Check that DTC P0979 recurs.
Is DTC P0979 indicated?
YES -
Go to Step 7 .
NO -
Go to Step 4 .
  1. 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 .
  1. 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.
  1. 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.
  1. Turn the ignition switch to LOCK (0).
  1. Jump the SCS line with the HDS.
  1. Disconnect PCM connectors B (49P) and C (49P).
  1. 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 .
  1. Disconnect the shift solenoid harness connector.

  1. 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 .
Is shift solenoid valve C OK?
YES -
Go to Step 14 .
NO -
  1. Disconnect PCM connector A (49P).
  1. Turn the ignition switch to ON (II).

  1. 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 .
  1. Connect PCM connectors.
  1. 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.
  1. 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 .
  1. 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.
  1. Reconnect all connectors.
  1. Clear the DTC with the HDS.
  1. 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.
  1. 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 .
  1. 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.