Automatic Transmission Diagnosis
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
Many transmission faults will set one or more diagnostic trouble codes (DTCs) in the PCM/ TCM. In some instances a group of diagnostic trouble codes (DTCs) may indicate a particular fault. The transmission may only operate in default or failsafe modes while certain diagnostic trouble codes (DTCs) are set.
Begin diagnosis by carrying out the PCM self-tests: KOEO and CMDTC and KOER and CMDTC. Record all diagnostic trouble codes (DTCs) and related freeze frame data. Clear the diagnostic trouble codes (DTCs) after recording the information.