System Diagnosis

The self-diagnostic capabilities of this system, if properly utilized, can simplify testing. The ECU monitors several different fuel injection system input and output circuits. If a problem is sensed with a monitored circuit, a fault code is stored in the ECU.

The CHECK ENGINE light will illuminate and ECU will start a compensation sequence and go into an emergency mode. This will allow vehicle to be operated until proper repairs can be made. Fault codes will stay in memory as long as ECU has battery power. There is no way to tell how long a code has been present. All fault codes are critical except speed sensor. To clear codes, refer to CLEARING CODES  in this article.

The setting of a specific fault code is the result of a particular system failure, NOT the reason for that failure, such as failure of a specific component. The existence of a particular code denotes the probable area of the malfunction, not necessarily the failed component itself.