Fuel Tank Fuel Pump Module
The fuel tank fuel pump module is located inside of the fuel tank. The fuel tank module consists of the following major components:
- The fuel level sensor
- The fuel pump and reservoir assembly
- The fuel strainer
Fuel Level Sensor
The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the position of the float arm. The Fuel Pump Power Control Module sends the fuel level information via high speed CAN - bus to the engine control module (ECM). The ECM then sends the fuel level percentage via low speed CAN - bus to the instrument panel cluster (IPC) in order to control the fuel gauge. The control module monitors the signal circuit of the fuel level sensor in order to determine the fuel level.
Fuel Pump
The fuel pump is mounted in the primary fuel tank module reservoir. The engine control module (ECM) supplies voltage to the fuel pump driver control module for 30 s when the ignition is turned on and continuously when the engine is running. While this voltage is being received, the ECM sends a serial data signal to the fuel pump driver control module containing the desired fuel pump speed. The fuel pump driver control module actuates the brushless fuel pump by means of a three phase signal and controls the fuel pump speed according to serial data signals received from the ECM containing the desired fuel pump speed. During a cold start, in order to warm the fuel the high pressure pump operates at full output and the pressure in the rail is regulated by fuel pressure regulator 2. This mode is also active during fuel injection cut-off. When in this mode, the fuel return line can flow up to 230 l/h (60.8 g/h).
Fuel Strainer
The fuel strainer attaches to the lower end of the fuel tank fuel pump module. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer is self-cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment.