System Diagnostics: Notes

The self-diagnostic capabilities of this system, if properly utilized, 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, SBEC memory stores a fault code, the CHECK ENGINE light glows 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, see FAULT CODES  table to determine the questionable circuit. Test circuits and repair or replace components as required. If problem is repaired or ceases to exist, the SBEC cancels fault code after 50 ignition on/off cycles. To clear codes, see CLEARING FAULT CODES  .

A specific fault code results from a particular system failure. A fault code does not condemn a specific component; component is not necessarily the reason for failure. Fault codes only call out a probable malfunction area.