Notes on Reading Diagnostic List

Notes on reading diagnostic list:
The systems to test are listed in the order of probability of cause of the problem.

The numbers in parentheses ( ) are the blink codes that would be displayed at the MALFUNCTION INDICATOR LAMP for the indicated system.

This symbol,(*), means that the MALFUNCTION INDICATOR LAMP stays on without blinking , when the SERVICE CHECK CONNECTOR jumped. In most cases this indicates that the Engine Control Module (ECM) has gone into "Back-Up" mode and assumed a pre-programmed default setting instead of the normal self-correcting function.

This symbol, (**), indicates that when the "CHECK ENGINE" light is ON, the idle speed will increase due to "Fail Safe" operation. The ECM will raise the idle speed to reduce the possibility of engine overheating or stalling.

Before performing any tests, visually check:
- Vacuum hoses for splits, kinks and proper routing.
- Ignition wires for cracking, hardness and proper connections at both the distributor and spark plugs.
- All wiring for proper connections, pinches and cuts.
- Wiring harnesses for proper routing.