Alternative Fuel Engine Control Module (AF ECM)

The AF ECM controls the bi-fuel CNG fuel system and determines which fuel system will operate the engine. The AF ECM monitors various engine and vehicle functions to provide the correct amount of CNG fuel under all operating conditions. This provides excellent driveability and fuel economy while maintaining reduced emission levels. When operating on gasoline, the AF ECM will turn the fuel indicator lamp ON. The fuel indicator lamp is located within the fuel gauge select switch. The fuel indicator lamp is also turned ON for a two-second bulb check whenever the ignition is turned ON.

The AF ECM is connected to the vehicles original gasoline control module (VCM, PCM or ECM) wiring harness. This allows the AF ECM to monitor the same engine controls sensors that the gasoline control module monitors. These include but are not limited to the ECT, IAT and TP sensors. Both the AF ECM and the gasoline control module monitor these sensors and circuits for faults. The gasoline control module does not control CNG fuel delivery, however gasoline engine operation and the ignition system are still monitored and controlled by the gasoline control module.