S80 AWD V8-4.4L VIN 85 B8444S (2008)
The fuel pump control module is called PEM (Pump Electronic Module). It powers the fuel pump and regulates the output of the pump. The fuel
pressure changes with the output of the pump.
The fuel pump control module is supplied with battery voltage by the fuel pump (FP) relay and is grounded in the car body. The fuel pump (FP) relay is
controlled by the central electronic module (CEM) when requested by the engine control module (ECM).
The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.
The fuel pump control module is controlled by the engine control module (ECM) via serial communication. The fuel pump control module then controls
the fuel pump by transmitting pulse width modulated (PWM) voltage on the ground lead for the fuel pump. This means that the voltage drop across the
pump changes, and with it the output of the fuel pump. See also: Function, B8444S See: Computers and Control Systems/Description and
Operation/Engine Control Module (ECM)/Function
There are no diagnostics for the fuel pump control module. The engine control module (ECM) has diagnostics for fuel pressure regulation and the
associated components. See also: Fuel pressure regulation, diagnostics See: Computers and Control Systems/Description and Operation/Fuel Pressure
Control, Diagnostics
The pulse width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read off using the diagnostic
tool.
The fuel pump control module is on the outside on the right-hand side of the fuel tank.
Valve variable intake
The valve for variable intake controls the vacuum motor for the damper in the variable intake manifold.
The valve consists of an electro-magnetic valve which controls the air flow between the vacuum tank and the vacuum valve for the damper in the
variable intake manifold.
The valve is supplied with voltage from the system relay via fuse and ground (control) internally in the engine control module (ECM). Also see:
Function, B8444S See: Computers and Control Systems/Description and Operation/Engine Control Module (ECM)/Function
The valve for variable intake can be diagnosed by the engine control module (ECM).
The valve for variable intake is on the right-hand side of the engine beside the intake manifold.
Emissions warning lamp
