Ford Workshop Service and Repair Manuals

Engine power and torque - vehicles with a 125 PS engine

General overview

The engine is controlled by the PCM (powertrain control module).

With the aid of a number of sensors the PCM calculates the optimum ignition timing, the optimum injected fuel quantity and injection timing, as well as the position of the throttle valve. In addition, a number of corrections are made, such as the adaptation of the ignition timing with the aid of the KS (knock sensor) or the adaptation of the fuel quantity by the lambda control.

Powertrain control module (PCM)

The PCM communicates with all motor sensors and the other modules. Communication of the PCM with the other modules and the system diagnostics takes place via the CAN (controller area network) data bus.

The following functions are regulated or controlled by the PCM:

• Fuel supply to the engine including lambda control
• Ignition setting including knock control
• Idle speed control
• Control of optimum valve timing via the camshaft adjustment for intake and exhaust camshafts
• Control of A/C compressor via the A/C clutch relay
• Control of EVAP (evaporative emission) purge valve

The PCM is mounted on the screen washer container in the front left wheel arch. It is protected by a plastic covering. On right hand drive vehicles a protective metal plate is also installed to prevent the plug connector from being pulled off, or make it harder to pull off, in case of theft. The protective plate is secured with a shear bolt. The shear bolt needs to be drilled out in order to remove the protective plate.

Knock sensor

Together with the KS, the PCM monitors the combustion process. When fitting, adhere strictly to the specified tightening torque, otherwise the KS will not work properly.

Camshaft Position (CMP) sensor

The CMP (camshaft position) sensors supply signals to the PCM, on the basis of which the camshaft position is calculated and the VVT (variable valve timing) solenoids actuated.

Crankshaft Position (CKP) sensor

The CKP (crankshaft position) sensor supplies the PCM with information about the engine speed and the position of the crankshaft.

Heated oxygen sensor (HO2S) and catalyst monitor sensor

The HO2S (heated oxygen sensor) measures the amount of oxygen in the exhaust system before the TWC (three-way catalytic converter). The catalyst monitor sensor measures the amount of oxygen in the exhaust system after the TWC. Both sensors transmit this data to the PCM. The PCM then corrects the air/fuel ratio and the ignition timing where appropriate. It also determines the efficiency of the TWC.

Variable Valve Timing (VVT) solenoid

The VVT solenoids control the valve timing adjustment, making it earlier or later. This increases engine performance and reduces unburnt hydrocarbons and oxides of nitrogen in the exhaust system.

Mass Air Flow (MAF) sensor

The MAF (mass air flow) sensor is located on the outlet side of the air filter housing and works according to the hot-wire principle. The PCM needs the signal to calculate the air mass. The MAF sensor has an integrated IAT (intake air temperature) sensor which is used to determine the intake air temperature.

Accelerator pedal position (APP) sensor

The APP (accelerator pedal position) sensor identifies the current position of the accelerator and sends this to the PCM and the GEM (generic electronic module).

Clutch pedal position (CPP) switch

The CPP (clutch pedal position) switch is mounted on the clutch pedal.

The CPP switch sends an earth signal to the GEM as soon as the clutch is depressed. This signal is passed on by the GEM via the CAN bus to the PCM.

On vehicles with a Start/Stop button an additional switch is fitted which sends a signal to the PCM when the clutch pedal is fully depressed.

Brake pedal position (BPP) switch

The BPP (brake pedal position) is informed via the PCM switch whether the brake pedal is depressed. This information is needed for emergency operation if the APP sensor fails. In addition, a signal is forwarded from the stoplamp switch directly via the GEM to the PCM.

Air Conditioning (A/C) Pressure Sensor

The A/C pressure sensor sends a continuous analogue signal to the PCM, which reflects the pressure status in the A/C high pressure line.

Air conditioning clutch relay

The air conditioning clutch relay energizes the air conditioning clutch solenoid. It is controlled by the PCM.

Throttle control unit

CAUTION:The throttle control unit must not be repaired or adjusted. The stop of the throttle valve must on no account be adjusted.

The throttle control unit receives a signal from the PCM. An electric motor then moves the throttle valve shaft by means of a set of gears.

The position of the throttle flap is constantly measured via the TP sensor and sent to the PCM.

Engine Oil Pressure (EOP) switch

The EOP (engine oil pressure) switch connects earth to the PCM depending on the engine oil pressure. This signal is needed to control the VVT solenoid and is sent via the CAN databus to the instrument cluster (oil pressure warning light).

Engine Coolant Temperature (ECT) sensor

The ECT (engine coolant temperature) sensor is designed as an NTC (negative temperature coefficient) resistor and is used to measure the exact ECT. The ECT is sent via the CAN databus to the instrument cluster (ECT display).

Evaporative emission canister purge valve

The EVAP purge valve is used to regenerate the activated charcoal filter and in certain operating conditions is controlled by the PCM.

Cooling fan module

The cooling fan module is mounted on the cooling air duct. It controls the speed of the cooling fan via a PWM (pulse width modulation) signal from the PCM.

Power Steering Pressure (PSP) switch

The PSP (power steering pressure) switch connects earth to the PCM depending on the pressure in the line between the power steering pump and the steering gear. In this way the PCM is able to adjust the engine speed under certain operating conditions.

Injectors

The electromagnetic injectors dose and atomize the fuel. The quantity of injected fuel is regulated by the opening duration of the injectors. Each cylinder has its own injector. The opening duration and the precise timing of opening are determined by the PCM.

Electronic Ignition (EI) coil

The EI coil is mounted on the side of the cylinder head. The electronic ignition system is a totally electronic, distributorless ignition system without any moving parts.

Alternator control (Smart Charge)

With the Smart Charge alternator, the voltage regulator functions remain unchanged, but the voltage setpoint is calculated in advance by the PCM and sent via the LIN (local interconnect network) databus to the alternator. This voltage setpoint is accepted by the voltage regulator of the alternator as the the new setpoint.

Starter system (Smart Starting)

As soon as the engine exceeds a certain speed, the PCM disconnects the starter relay and so turns off the starter. This shortens the starting process and protects the starter.

The signal of the CKP sensor is used for monitoring the starting procedure.