General Description

The Alternate Fuel Engine Control Unit (AF ECU) controls alternative fuel engine operation. The control unit monitors various engine and vehicle functions to provide the correct amount of fuel under all operating conditions. This provides excellent driveability and fuel economy while maintaining exhaust emission levels.

In addition to controlling engine operation the AF ECU also runs tests (DTCs) on various sensors and outputs. If a DTC detects a problem the AF ECU will store the DTC number along with sensor information retrieved at the time of the problem (Freeze Frame). The DTC number and any Freeze Frame information can be retrieved from the AF ECU using a scan tool.