Description of On-Board Diagnostics

Each diagnostic trouble code is diagnosed by following a specific testing procedure. The diagnostic test procedures contain step-by-step instructions for determining the cause of trouble codes. It is not necessary to perform all of the tests to diagnose an individual code.

The body control module will set a diagnostic trouble code if a monitored input is determined to be malfunctioning and the trouble condition remains active for 10 consecutive seconds. Once the trouble condition is removed, the body control module will back out the diagnostic trouble code if the trouble condition remains cleared for twenty ignition cycles.

Always begin by reading the diagnostic trouble codes using a scan tool. This procedure begins with the Symptom Identification TEST-1A - Identifying Vehicle Equipment and System Problems. This will direct you to the specific test(s) that must be performed.