Fuel Level Sensors
| ITEM | DESCRIPTION |
|---|---|
| 1 | Fuel level sensor |
| 2 | Fuel level sensor float arm |
| 3 | Fuel level sensor float |
Two fuel level sensors are installed in either side of the saddle tank. One is mounted on the fuel pump module and is known as fuel level sensor 'A', the other is mounted on the carrier in the left side of the fuel tank and is known as fuel level sensor 'B'. The sensors are a float operated MAPPS (MAgnetic Passive Position Sensor) which provide a variable resistance to ground for the output to the fuel level gauge in the instrument cluster. The sensor is sealed from the fuel preventing contamination of the contacts, increasing reliability. The fuel level sensors are connected to the external electrical connector on the flange via the connector on the underside of the fuel pump module flange.
The sensor comprises a series of resistors mounted in an arc on a ceramic surface. The resistors are wired in series with individual contacts. A soft magnetic foil with flexible contacts is mounted a small distance above the film resistors. A magnet, located below the ceramic surface, is attached to the sender unit float arm. As the float arm moves, the magnet follows the same arc as the film resistors. The magnet pulls the flexible contacts onto the opposite film resistor contacts forming an electrical circuit.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Magnetic foil |
| 2 | Spacer |
| 3 | Ceramic surface |
| 4 | Magnet |
| 5 | Resistance film |
The film resistors are arranged in a linear arc with resistance ranging from 51.2 to 992.11 Ohms. The electrical output signal is proportional to the amount of fuel in the tank and the position of the float arm.
The measured resistance is processed by the instrument cluster to implement an anti-slosh function. This monitors the signal and updates the fuel gauge pointer position at regular intervals, preventing constant pointer movement caused by fuel movement in the tank due to cornering or braking.
A warning lamp is incorporated in the instrument cluster and illuminates when the fuel level is low.
The fuel level sensor signal is converted into a CAN message by the instrument cluster as a direct interpretation of the fuel tank contents in liters. The ECM uses the CAN message to store additional OBD (On-Board Diagnostic) 'P' Codes for misfire detection when the fuel level is below a predetermined capacity.