Exhaust Gas Recirculation System Monitor

Exhaust Gas Recirculation System Monitor (V8 Engines)

High/Low Input Failure
These are continuous monitors. The voltage from the sensor is compared to a failure threshold defined in the software.

If the voltage is below the low threshold, then a timer starts to increment. Once this timer exceeds another threshold, then a failure flag is set and a DTC is stored.

If the voltage is over the high threshold defined in the software, then a timer starts to increment. Once this timer exceeds a threshold, then a failure flag is set and a DTC is stored.

Exhaust Gas Recirculation Valve Range/Performance Failure
The method employed to check the EGR valve operation involves forcing the valve open and closed during an over run fuel cut off. A reading from the MAP sensor is checked before, during and after the valve operation. The difference in values between the open and closed states of the valve is checked against a map of engine RPM versus the difference value. If this calculated value is below or over the threshold, a failure is judged.