G81 fuel temperature sensor. 1.9 TDI PD from VAG Group. Family of diesel engines with injection pump-injector
G81 fuel temperature sensor
The G81 fuel temperature sensor is located in the return fuel line between the fuel pump and the fuel cooler. It determines the current fuel temperature at this point. The G81 fuel temperature sensor has a negative temperature coefficient. The resistance of the sensor decreases with increasing fuel temperature.
The signal generated by the G81 fuel temperature sensor is used by the J248 Direct Fuel Injection Control Engine to determine the fuel temperature. This signal is needed to calculate the start point of the injection point and the amount of injection so that the fuel density at different temperatures can be taken into account. This signal is also used to determine when the fuel cooling pump is turned on.
Consequences of signal failure
If the G81 fuel temperature sensor signal fails, the direct fuel injection engine control module J248 calculates a new value based on the signal generated by the engine coolant temperature sensor G62.
G81 Fuel temperature sensor.
J248 Direct fuel injection engine control module.
Read more about the family of diesel engines with injection pump-injector here .