System Description
Computerized Engine Controls:
The engine systems in this vehicle are controlled by a digital, pre-programmed, engine controller (formerly called a "Single Board Engine Controller" or "SBEC"), which has the ability to update and revise its programming to meet changing operating conditions. The engine controller provides precise control of, air/fuel mixture, ignition timing, emission control devices, cooling fan, charging system, and idle speed.
Various sensors provide necessary input for the engine controller to function correctly. Some of these include the Manifold Absolute Pressure Sensor, Throttle Position Sensor, Oxygen Sensor, Coolant Temperature Sensor, and Vehicle Distance Sensors. In addition to these sensors, various switches and relays are used to carry out commands or outputs from the engine controller.
The engine controller monitors many of its input and output circuits. If a fault is detected in any monitored system, this information is stored in memory and displayed by the CHECK ENGINE light on the instrument panel. If a fault has been detected, the fault information can be read through the instrument panel CHECK ENGINE lamp or diagnostic scan tool. If the CHECK ENGINE lamp indicates that a problem exists or there is a code other than code 55 set in memory this problem should be corrected before proceeding with other diagnosis.