Engine Controls - Tests W/Codes: Introduction

For automatic transmission testing and diagnosis, see M24A ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.

If no faults were found while performing BASIC TESTING article in this section, proceed with self-diagnostics. If no trouble codes or only pass codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).