Fuel Level Sensors

WARNING: This page is about a different car, the 2018 Land Rover Discovery and 2017 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.

Two fuel level sensors are used to measure the amount of fuel remaining in the left and right sides of the fuel tank. The left passive fuel level sensor 'B' is attached to the tank internal bracket. The right active fuel level sensor 'A' is attached to the outside of the fuel pump swirl pot. Both sensors are connected to the vehicle wiring harness via the external electrical connector on the fuel pump module top flange assembly.

Both level sensors are MAgnetic Passive Position Sensors (MAPPS) which provide a variable resistance to ground for the output from the fuel gauge.

The electrical output signal varies to the amount of fuel remaining in each side of the fuel tank and the position of the float arms. The resistance is measured by the fuel level sensors and the information passed to the Body Control Module/Gateway Module (BCM/GWM) assembly which implements an anti-slosh function. This monitors the signal and updates the fuel level signal to the Instrument Cluster (IC) at regular intervals. The anti-slosh function prevents constant pointer movement caused by fuel movement in the tank due to cornering or braking. A low level fuel warning indicator is incorporated in the IC which illuminates when the fuel level in the tank falls below a predetermined level.

The fuel level sensor signals are converted into High Speed (HS) Controller Area Network (CAN) comfort system bus messages by the BCM/GWM assembly. The messages are used by the IC to display the remaining fuel level and low fuel warning. The BCM/GWM assembly messages are monitored by the PCM to store Diagnostic Trouble Code (DTC) for misfire detection when the fuel level is below a predetermined capacity.

North American Specification (NAS) market vehicles have a Diagnostic Module Tank Leakage (DMTL) pump for leak detection requirements which have additional connections, hoses and pipes. For additional information, refer to: EVAPORATIVE EMISSIONS .