Fuel pump

Fig 1: Fuel Level Sensor (Gasoline/Diesel)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The fuel pump (FP) is located on the inside of the fuel tank on the right-hand side. The power supply for the pump is checked by the central electronic module (CEM) which operates a relay. This relay controls the power supply to the pump and is directly connected to the central electronic module (CEM).

The central electronic module (CEM) uses the controller area network (CAN) to communicate with the engine control module (ECM) which requests power to the pump system. The active-on-demand pump system that receives a control signal from the engine control module (ECM) to control the flow.

The central electronic module (CEM) also communicates with the supplemental restraint system (SRS) module via a directly connected signal. In the event of a collision, the supplemental restraint system module (SRS) transmits data and the central electronic module (CEM) closes the relay for the pump system and shuts off the power supply to the fuel pump (FP).

There are diagnostics for the input signal from the engine control module (ECM) and for the relay for the fuel pump (FP).

In the event of a fault in the controller area network (CAN) or central electronic module (CEM), there is a limp-home function in the central electronic module (CEM). This keeps the fuel pump (FP) relay active throughout the operating cycle.

This function is stopped in the event of a collision. A signal is transmitted from the supplemental restraint system module (SRS) to the central electronic module (CEM).

If there are electrical faults, the engine cannot be restarted after a collision.