Back Up Facility

Back Up Facility

In the event of certain input failures, the ECM will implement a back-up air fuel ratio to maintain driveability. A back-up value is provided for the ECT sensor, the IAT sensor and the MAP sensor.

Back Up Values:

• Coolant sensor 60°C
• Inlet air sensor 35°C

Manifold absolute pressure The ECM implements air fuel ratio relating to engine speed and throttle position.

Throttle position (TP) sensor The TP sensor is a potential divider which is connected to the throttle disc spindle. The ECM provides a 5 volts supply to the TP sensor and an earth return. A third wire is connected to the sensor and transmits a voltage output signal back to the ECM indicating the rate of throttle opening.

Exhaust Emission Control (closed loop) The ECM uses a signal from the HO2S to control exhaust emissions. This system control the air/fuel ratio to 14.7:1 at idle and cruise conditions.

Fuel temperature sensor ( T Series only ) The fuel temperature sensor is inserted in the fuel rail and measures fuel temperature. During engine cranking at high temperatures, The ECM increases fuel supply, and opens the throttle disc via the IACV to aid hot starting.