Transmission Control Systems: Testing and Inspection

40/41TE PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE

For a complete wiring diagram Refer to Diagrams/Electrical. Electrical Diagrams

- Many transmission symptoms can be caused by a low fluid level. If the fluid level is low, locate and repair any leaks and fill the transmission to the proper fluid level.
- Testing should only be performed with the battery fully charged to avoid false diagnosis.
- With the scan tool, read Engine (PCM) DTCs. If Engine DTCs are present, perform the appropriate diagnostic procedure(s) before proceeding.
- With the scan tool, read Transmission (TCM) DTCs. Record all Stored, Active, and Pending DTC information. Diagnose any Pending DTC as a matured DTC.
- With the scan tool, read and record any DTC EVENT DATA. Use this data to help identify the conditions in which the DTC was set.

NOTE: DTC Event Data may exist even if no DTCs are stored. DTC Event Data is only erased by a Battery Disconnect, reflash, or QuickLearn procedure. Clearing DTCs does NOT erase the DTC Event Data. Some DTCs require two "bad trips" before they are stored (and the MIL illuminates). The transmission may enter "limp-in" mode during the first "bad trip," but if the fault condition is not present after the vehicle is restarted, the pending DTC may be cleared without lighting the MIL. Nevertheless, the DTC Event Data for the pending DTC will remain stored and can still be retrieved with the scan tool. If the customer reports a "limp-in" event but no DTCs are present, check the DTC Event Data.

NOTE: Performing a Battery Disconnect will clear all DTC EVENT DATA and may reset all learned Transmission values to the controllers default values, which could cause erratic shift schedules.

- With the scan tool, perform the Shift Lever Position Test. If the test does not pass, refer to the diagnostic procedure for P0706-Transmission Range Sensor Rationality. P0706
- For Gear Ratio Error DTCs, use the scan tool to read and record the Clutch Volume Index (CVI) information.
- Refer to the When Monitored and Set Conditions for this DTC. DTCs can set at ignition on, at start up, driving under specific conditions, or after controller diagnostic monitors have run.
- Refer to applicable Technical Service Bulletins (TSBs) for controller software update information. Some conditions can be corrected by upgrading the Engine (PCM) or Transmission (TCM) controller software.
- Check for any Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

Were there any repairs made that fixed the vehicle?

Yes

- Testing complete.
- Perform 40/41TE VERIFICATION TEST Verification Tests

No

- Refer to the Transmission and Drivetrain and perform the appropriate diagnostic procedure(s).