The PCM is built into the resonance chamber in the front left-hand fender and has three electrical connectors with a total of 128 pins.
The PCM monitors and processes the signals from the sensors. The fuel injectors, the fuel metering valve and the fuel pressure control valve are also controlled by the PCM .
The PCM can be diagnosed through the DLC using WDS.
BPPswitch and brake light switch
NOTE:Refer to the current service literature for the exact procedure for installing the brake light switch and BPP switch.
The BPP switch is connected to the instrument cluster via the CAN bus.
The BPP switch is closed when de-energised and sends a ground signal to the PCM.
The brake light switch is connected with the PCM via a conventional cable connection.
The brake light switch is open when de-energised. When the brake light switch is closed, it sends 12V to the PCM .
The signals of the BPP switch and the brake light switch are used if the APP sensor should fail.
In this instance, the PCM compares the signals of the BPP switch and brake light switch.
APP sensor
The APP sensor is a double contactless inductive sensor.
For safety reasons, the APP sensor consists of two sensors.
If the APP sensor malfunctions when the vehicle is in operation, a fault code will be stored in the PCM.
If one of the sensors in the APP sensor should fail, the engine will operate at reduced power. However, it is still possible to reach top speed.
If the vehicle is fitted with a driver information system, the fault message "REDUCED ACCELERATION" will be displayed.
If the both sensors of the APP switch fail, after a single operation of the BPP switch and the brake light switch and then after a plausibility check, the engine is controlled up to a speed of 1200 rev/min. The vehicle can be accelerated to a maximum speed of 56 km/h.
When the BPP switch and the brake light switch are actuated again, engine speed will drop to idle speed. Once the BPP switch and the brake light switch are de-energised again, engine speed is increased again.
If the vehicle is fitted with a driver information system, the fault message "REDUCED TOP SPEED" will be displayed.
If the vehicle is not fitted with a driver information system, the engine system fault warning light will come on to indicate a system fault.
CKP sensor
The CKP sensor is attached to the oil pump housing, behind the crankshaft timing pulley.
The CKP sensor detects a magnetic disc with 58+2 magnetic pole pairs on it, arranged around the circumference.
The CKP sensor uses the Hall effect principle.
CMP sensor
The CMP sensor is located behind the exhaust camshaft timing pulley.
The CMP sensor is attached to the valve cover by means of a slot on the sensor housing.
When carrying out installation work, ensure that the gap between the CMP sensor and exhaust camshaft timing pulley is correct.
The CMP sensor uses the Hall effect principle.
For detection of cylinder "1" different sized windows have been milled into the exhaust camshaft timing pulley.
During starting, the CKP sensor and the CMP sensor are synchronised. If both signals are present, the engine will be started.
If the signal from the CMP sensor fails while the engine is running, the engine continues to run using the signals from the CKP sensor.
If the CMP signal is missing at the next starting operation, it will not be possible to start the engine.
MAF sensor
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Mark showing installation orientation
The MAF sensor (1) is located on the outlet of the air filter housing.
When installing the connecting piece, ensure correct orientation; the arrow (2) must be pointing in the direction of flow of the drawn-in air.
The MAF sensor calculates the quantity of fresh air drawn in.
The signal from the MAF sensor is used by the PCM to regulate the EGR system and the amount of recirculated exhaust gas.
MAP sensor
The MAP sensor is positioned in the inlet manifold, behind the air shutoff throttle.
The MAP sensor measures the absolute intake pipe pressure, which is a reference value for engine load.
The signal from the MAP sensor is required by the PCM to control the boost pressure of the variable turbocharger.
Turbocharger position sensor
The shutoff solenoid valve is attached to the front module next to the air filter housing; during the engine warm-up phase, it shuts off the flow of coolant to the coolant reservoir.
It is actuated by the PCM using pulse width modulation.
The PCM processes the signals from the ECT sensor to calculate how long the shutoff solenoid valve is to be actuated for.
Bypass solenoid valve
The fuel metering valve adjusts the quantity of fuel to the high-pressure pump elements as a function of engine operating conditions. This improves engine efficiency.
The fuel metering valve is controlled by the PCM using pulse-width modulation.
The fuel metering valve is closed when de-energised.
Fuel pressure control valve
The fuel pressure control valve is screwed directly onto the high pressure outlet of the fuel pump.
The fuel pressure control valve regulates the fuel pressure at the high-pressure outlet and thereby the fuel pressure in the common rail.
In addition, the fuel pressure control valve dampens pressure fluctuations which arise when the fuel pump is supplying fuel and as a result of the injection process.
Fuel pressure sensor
The fuel pressure sensor is located at the side on the common rail and measures the fuel pressure in the common rail.
The fuel pressure sensor consists of a piezoelectric element that sends a variable voltage signal to the PCM, as a function of fuel pressure.
The PCM uses this signal to calculate how long the injectors are to be actuated for and to regulate the fuel pressure by means of the fuel pressure control valve.
Fuel temperature sensor
