Fail-Safe System

PURPOSE
The fail-safe system makes it possible to start and drive the vehicle if something malfunctions in the Central Processing Unit (CPU) circuit of the PCM or if the PCM detects complete failure of a major input device.

LOCATION
The system is built-in to the PCM

OPERATION
Fuel injection and ignition timing are controlled within preset parameters if the PCM detects failure within one or more of the following components:

^ Mass Air Flow Sensor
^ Engine Coolant Temperature Sensor
^ Knock Sensor
^ Camshaft Position Sensor
^ Throttle Position Sensor
^ CPU of the PCM


When in fail-safe, the vehicle will run but engine speed will be limited to 2400 rpm. The CHECK ENGINE light will also come on to alert the driver of the problem.