Automatic Transmission Diagnosis
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
- KOER and CMDTC
For vehicles equipped with a TCM, carry out the TCM self-test.
Record all diagnostic trouble codes (DTCs) and related freeze frame data. Clear the diagnostic trouble codes (DTCs) after recording the information.