Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Fuel Temperature Sensor



Fuel Temperature Sensor

The fuel-temperature sensor is installed in the fuel line just before the high-pressure pump, and employs a variable resistor (NTC= Negative Temperature Coefficient) to monitor fuel temperature.
The fuel temperature serves as a measured variable for the following functions:
- Engine overheating protection
- Fuel injection rate calculation
- Calculation of the requirement for the pre-supply pump
- Pressure wave correction:
In the case of a Common Rail System with more than one injection, each injection triggers a pressure wave in the line from the rail to the injector and in the high-pressure holes of the injector. This pressure wave influences the injection rate of the subsequent injections. In order to be able to use injections with variable gaps, this influence must be minimised depending on the gap between injections, the rail pressure and the fuel temperature.

Fault handling
The fuel temperature sensor is monitored for electrical faults and plausibility. A short circuit can destroy the fuel-temperature sensor.