Fail-Safe Function

When a malfunction has occurred in specific areas of engine and emission control system, ECM enters "fail-safe function". When vehicle is operating in fail-safe function, ECM allows a lower level of engine performance to be available, allowing vehicle to be driven for service. When malfunction occurs a failure signal is sent to ECM, and ECM control over affected sensors and actuators is maintained on the basis of standard signals and/or a back-up program stored in ECM. While in fail-safe mode ECM ignores failure signal and/or CPU inputs. ECM will remain in fail-safe mode as long as malfunction is detected, fail-safe mode is canceled when ECM detects normal conditions.