Quick Test Description

Fig. 33 Code Interpretation Using Check Engine Light:

The MIL light is intended to alert the driver of certain malfunctions in the engine control system. If such a fault occurs, the EEC-IV processor will substitute a value or values and continue operating. In some cases this action may result in a slight change in vehicle driveability.
The check engine light can be used to read codes. The check engine light on the front dash panel will remain on when a hard fault is present. During the Self-test sequence, a service code is reported by the check engine light. It will represent itself as a flash on the check engine light display on the dash panel, Fig. 33. A single digit number of three will be reported by three flashes. However, as previously stated, a service code is represented by a two digit number, such as 2-3. As a result, the Self-test service code of 2-3 will appear on the check engine light display as two flashes, then after a two second pause, the light will flash three times.
Continuous Memory codes are separated from Key On Engine Off codes by a six second delay, a single half-second flash, then another six second delay.