Theory Of Operation
The PCM compares actual shutdown time to a calculated shutdown time value. The calculated shut down time value is based on the amount of shutdown time necessary for the ECT to drop a specific amount after a completely warmed up engine is shut down. If the difference between actual shutdown time and the calculated shut down time is greater than a maximum value, a one trip failure will set. The shutdown time is measured again after 1 hour of ignition off time following the next engine warm up cycle. The PCM compares the shutdown time to a calculated value. If the difference is greater than a maximum value, the MIL is illuminated and a DTC will set.
The fuel level signal is a direct input to the Cluster. The fuel level signal is sent to the FCM over the CAN B bus circuit. The NGC receives the fuel level signal from the FCM over the CAN C bus circuit.