Diagnosing Automatic Transmission Conditions using GDS2 Session Logs

If a 2015-2019 GM model is being serviced for an automatic transmission operating condition or a vibration concern that can be duplicated, GDS2 should be used to aid in identifying the potential cause of the condition.

In some cases, it may be necessary to contact the GM Technical Assistance Center (TAC) for additional help with diagnosis. However, there have been many TAC cases where GDS2 was not used properly, adding to the time spent making a correct diagnosis and delaying repairs.

When calling TAC for assistance, a GDS2 session log will be requested for any automatic transmission conditions that can be duplicated. For U.S. dealerships, it’s recommended to submit a GDS2 session log to TAC by attaching it to the TAC case using the Dealer Case Management (DCM) system. (Fig. 15) TAC will review the session log and reply using the DCM. Refer to Bulletin #08-00-89-014 prior to providing the GDS2 session log to TAC.

Fig. 15

 

A GDS2 session log also can be emailed (Fig. 16) prior to contacting TAC for assistance by sending the session log to tacsnapshot@gm.com (U.S.) or tacsnapshotcanada@gm.com (Canada). Refer to #PIP4902 for more information.

Fig. 16

 

Before Contacting TAC

If servicing a vehicle with an automatic transmission condition, perform the following before contacting TAC:

  1. Check all modules for any DTCs.
  2. Record all DTCs found.
  3. Review the freeze frame data for any codes that have set.
  4. Clear the DTCs.
  5. Select the Transmission Control Module (TCM) under Modules in GDS2, and then select Transmission Data.
  6. Drive the vehicle under the conditions described by the customer when the transmission concern occurs or ask the customer to drive the vehicle to help duplicate the condition.

If any DTCs were set, refer to the GDS2 freeze frame data to help determine how the vehicle should be driven in order to duplicate the conditions that may cause the DTCs to set.

  1. If the condition can be duplicated, place a bookmark at the location(s) where it is present.
  2. Back out of the software to the Home screen and close the application.
  3. Review the GDS2 session log to help determine the root cause.

 

– Thanks to Terry Neuendorf

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One Comment

  1. Derrik Skidmore says:

    Wouldn’t be nice to have an advanced transmissions GDS2 diagnostics class that would educate service technicians to be able to effectively diagnose concerns without requiring a TAC snapshot? There are no training classes like this in GM STC.