Fail Safe Operation

ECU Back-up Functions

1. Fail-Safe Function
When an abnormality occurs in signal from a sensor, the ECU ignores that signals and assumes a pre-programmed value that allows the engine to continue to run.
2. Back-up Function
When an abnormality occurs in the ECU itself, the injections are controlled by a back-up circuit independent of the system in order to permit minimal driving.
3. Self-diagnosis Function (Check Engine warning light and LED indicator).
When an abnormality occurs in a signal from a sensor, the ECU lights the Check Engine warning light, stores the failure code in erasable memory and can indicate the code by flashing the Check Engine light. When the ignition is initially turned on, the ECU supplies ground for the Check Engine warning light for about 2 seconds.