System Diagnosis: Introduction

The self-diagnostic capabilities of this system, if used properly, can simplify testing. The Single Board Engine Controller (SBEC) monitors several different engine control system circuits.

If a problem is sensed with a monitored circuit, a fault code is stored in the SBEC, the CHECK ENGINE light illuminates and SBEC enters limp-in mode. In limp-in mode, SBEC compensates for component failure by substituting information from other sources. This allows vehicle operation until repairs can be made.

Once codes are known, refer to FAULT CODES listed in this article to determine the questionable circuit. Test circuits and repair or replace components as required. If a problem is repaired or no longer exists, SBEC cancels fault code after 50 ignition on/off cycles. To clear codes, refer to CLEARING CODES  in this article.

A specific fault code indicates a particular system failure, but it DOES NOT indicate that cause of failure is necessarily within system. The fault code DOES NOT condemn any specific component; it simply points out a probable malfunctioning area.