Component description for the fuel pump control unit - GF47.40-P-2001MOS

ENGINE 275.953 in MODEL 216.376, 221.176 as of Model Year 09 /AEJ 08 

LH rear compartment shown on model 221 

Location 

The fuel pump control unit is located in the LH rear compartment.

Task 

The fuel pump control unit is supplied by "Siemens VDO Automotive AG" and carries the internal designation FSCM light (F  uel S  ystem C  ontrol M  odule light).

Through the fuel pump (M3), fuel pump control unit sets the fuel pressure to the preset specified value of 3.8 bar.

Input and output signals 

The following input signals are evaluated by the fuel pump control unit and appropriate output signals are emitted:

• Direct input signals 
• Direct output signals 
• CAN input signals 
• CAN output signals 

Direct input signals 

• Terminal 15
• Circuit 30
• Tml. 31
• "Fuel pump ON" ground signal
• Sensor signal from fuel pressure sensor (B4/7)

Direct output signals 

• Power supply for fuel pressure sensor (5 V)
• Fuel ground pressure sensor
• Fuel pump + (12 V) (pulse width modulated signal (PWM signal))
• Fuel pump - (PWM signal)

CAN input signals 

• Diagnosis requests
• Data for variant coding

CAN output signals 

• PWM signal duty cycle (fuel pump actuation 0 to 100 %)
• Self-diagnosis data
• Requested diagnostic data

Design 

The fuel pump control unit consists of a fuel housing with two plugs and internal measuring and control electronics.

Function 

The function description is subdivided into the following points:

• Fuel pump regulation 
• Fuel pump limp-home mode control unit 
• Diagnosis 
• De-tanking service 

Fuel pump regulation 

The fuel pump is switched on when the fuel pump control unit receives the "fuel pump ON" ground signal directly from the ME-SFI control unit (N3/10).

The fuel pump control unit detects the current fuel pressure through the voltage signal from the fuel pressure sensor.

The fuel pump control unit evaluates the current fuel pressure, compares it with the preset specified value of 3.8 bar, and actuates the fuel pump with a PWM signal as required, so that the actual value corresponds to the specified value.

The fuel delivery capacity is up to 145 l/h.

Fuel pump limp-home mode control unit 

• To ensure security of fuel supply, the fuel pump control unit has a limp-home function, which is activated if there is an internal control system failure (for example, a processor fault).
• If the signal from the fuel pressure sensor is missing the fuel pump is actuated by means of an established permanent PWM signal (maximum delivery).
• If the signal "Fuel pump ON" in missing the fuel pump actuated upon recognition of "circuit 15".

Diagnosis 

The fuel pump control unit conducts an own and component check. Detected faults are stored by the fuel pump control unit and are available over the drive train CAN (CAN C) to the ME-SFI control unit and the Diagnosis Assistance System (DAS) when connected.

De-tanking service 

The fuel tank can be emptied over the fuel pump control unit without the engine running.

To do this the de-tanking service is called up using the DAS and the following parameters are entered:

• Parameter "01" for "fuel pump ON"
• Time "0-99999" seconds
• Specified fuel pressure 3.8 bar

During emptying the DAS must be connected and the ignition must remain on.

Variants 

The vehicle and engine variants are already stored in the fuel pump control unit. After replacing the fuel pump control unit a variant coding must be conducted.

	Wiring diagram for ME-SFI [ME] gasoline injection and ignition system control unit	N3/10 Vehicle connector (Sheet 1) model 216	PE07.61-P-2101-99SAF
		N3/10 Vehicle connector (Sheet 1) model 221	PE07.61-P-2101-99CAD
	Wiring diagram for fuel pump control unit	N118 Model 216	PE47.40-P-2101-99CAA
		N118 Model 221	PE47.40-P-2101-99SAA