Fuel Rail Temperature Sensor

Fuel Rail Temperature Sensor

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.

Range/Performance Failure
The monitor checks that the fuel rail temperature sensor signal is not stuck within the normal operating range. It checks that the signal has varied by a calibrated amount before the ECT signal has increased by 40 degree C and twenty minutes of engine running has elapsed. Maximum and minimum values of fuel rail temperature and ECT are continually calculated. If the difference between the fuel rail temperature maximum and minimum values is greater than the calibrated threshold then normal judgment is made. For failure judgment, the monitor can only flag a failure if a cold start is detected. A cold start is detected when the difference between the IAT and ECT is less than a calibrated value, and the ECT is less than a second calibrated value.