Automatic Transmission Diagnostic Strategy: Diagnostics

• Perform on-board diagnostic procedures Key On Engine Off (KOEO) and Key On Engine Running (KOER).

  See ON-BOARD DIAGNOSTIC TESTS .

• Record all diagnostic trouble codes (DTCs).
• Repair all non-transmission codes first.
• Repair all transmission codes second.
• Erase all continuous codes and attempt to repeat them.
• Repair all continuous codes.
• If only pass codes are obtained, proceed to Diagnosis by Symptom Charts for further information and diagnosis.

Follow the diagnostic sequence to diagnose and repair the concern the first time.