DTC Troubleshooting

DTC P1780: Problem in Shift Control System

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.

1. Clear the DTC with the HDS.
2. Test-drive the vehicle for several minutes with the shift lever in D, and let the transmission shift through all five gears, then slow down to a stop.
3. Turn the ignition switch to LOCK (0). Repeat step 2, then go to step 4.
4. Check for other DTCs indicated simultaneously with DTC P1780.

NOTE: DTC P1780 means there is one or more A/T DTCs about the shift control system.

Are there other DTCs?

YES - Troubleshoot the problem indicated by the DTC.

NO - Go to step 5.

5. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
6. Test-drive the vehicle for several minutes with the shift lever in D, and let the transmission shift through all five gears, then slow down to a stop.
7. Turn the ignition switch to LOCK (0). Repeat step 6, then go to step 8.
8. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.

Is DTC P1780 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 9.

9. Monitor the OBD STATUS for P1780 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 8, go to the indicated DTC's troubleshooting.

NO - Check for poor connections and loose terminals at 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 6 and recheck.