DTC P1780: Problem in Shift Control System

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the H DS, and review General Troubleshooting Information (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Test-drive the vehicle with the shift lever in D, and let the transmission shift through all five gears.
Check for other Pending or Confirmed DTCs with the HDS.
NOTE: DTC P1780 means there is one or more A/T DTCs stored for the shift control system.

Are there other DTCs?

YES -Refer to the TROUBLESHOOTING as indicated by the DTC.

NO -Go to step 5.
Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
Test-drive the vehicle with the shift lover in D, and let the transmission shift through all five gears.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P1780 indicated?

YES -If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 6. If the PCM was substituted, go to step 1.

NO -Go to step 8.
Monitor the OBD STATUS for P1780 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?

YES -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Pending or Confirmed DTCs were indicated in step 7, go to the INDICATED DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals at the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 6. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 6.