Description of the engine control system (with manual transmission) (Mondeo 1)

The engine control system has a large number of sensors, switches, magnetic valves, as well as an electronic engine control module EEC (A15), which regulates fuel access, exhaust gas recirculation, ignition operation, engine idle speed, fuel evaporation into the atmosphere and transmission operation.

Supply voltage

Terminal 1 of the EEC module (A15) is constantly supplied with voltage to maintain the stored information. When the ignition is switched on, the ignition coil, the EEC module relay (K31), and the HEGO sensor (Lambda probe, B3) receive voltage. All other components of the engine control system are supplied with voltage via the EEC module relay (K31). Terminals 37 and 57 of the EEC module (A15) receive current from the EEC module relay (K31) via soldered connection S55.

Ignition

For vehicles with a manual transmission, the ignition system is integrated into the EEC module (A 15). The ignition processor controls the ignition coil (T2) and the spark plugs via terminals 58 and 59 of the EEC module (A15).

Fuel pump

The fuel pump relay (K4) receives voltage from the EEC module relay (K31) and is controlled by terminal 22 of the EEC module (A15). Terminal 8 of the EEC module (A15) is used as a control input for the fuel pump. Current flows to the pulse switch (N61), which switches off the fuel pump in the fuel tank (A31) in the event of an emergency. The fuel pump is always on during normal operation and maintains pressure in the system even if the engine is switched off.

Power Steering Pressure Switch

The power steering pressure switch (N96) sends a signal to terminal 28 of the EEC module (A15) when the pressure is high. When the power steering pressure is high, the EEC module (A15) increases the idle speed.

Engine cooling

The engine ventilation relay (K45) and the engine fan motor (M37) are controlled by terminal 13 of the EEC module (A15). In a vehicle with air conditioning, the fan motor (M37) is additionally controlled by terminal 31 of the EEC module (A15) and by the dual pressure switch (N76).

On-board computer module

The on-board computer receives the fuel consumption value from terminal 34 of the EEC module (A15), as a result of which the fuel consumption indicator value is calculated, and the distance that can be traveled before the fuel tank runs out is displayed to the driver.

Adjusting the air conditioning compressor

The full load relay of the air conditioner (WOT, K32) is activated if terminal 54 of the EEC module (A 15) is connected to "ground". This causes the air conditioner compressor to switch off, and the engine load is reduced.

Voltage is applied to terminal 10 of the EEC module (A15) when the compressor switch (N75) is closed. Based on this information, the engine load and engine idle speed are calculated.

Fuel matching (octane adjustment)

The voltage difference across the octane control connector (P6) is measured via terminal 42 of the EEC module (A15) and this information is used to change the ignition timing.

Tachometer

The tachometer located on the instrument panel (combined instrument AZO) is connected to terminal 4 of the EEC module (A15).

Connection to ground and diagnostics

Terminals 17 and 48 of the module are connected to the EEC diagnostic connector (STAR). Terminals 18 and 19 of the module are connected to the EEC diagnostic connector (DCL). Terminals 16, 40 and 60 are connected to ground G1, and terminal 20 is connected to ground G19.

Magnetic valve

The injection solenoid valves (Y35, Y36 and Y38) are supplied with voltage via the EEC module relay (K31). Each of the four injection solenoid valves is controlled continuously and individually from terminals 58, 59, 39 and 35 of the EEC module (A15). The injection quantity, i.e. the duration of the input signal, is determined by the temperature, load and engine speed, as well as the composition of the exhaust gases. The longer the pulse duration, the greater the amount of fuel injected.

The idle speed control valve (Y13) receives the distribution voltage via the EEC module relay (K31). The EEC module (A15) compares the stored nominal engine idle speed value with the actual idle speed value and controls the idle speed control valve (Y13) via terminal 21. The idle speed control valve (Y13) varies the amount of air entering the engine via the additional air valve.

The solenoid valve for cleaning via the activated carbon filter (Y1) is used to open and close the chamber with activated carbon. The valve opens if terminal 11 of the EEC module (A15) is connected to ground. The fuel mixture can then be injected into the engine and burned there.

The air access control solenoid valve (Y34) is controlled by terminal 14 of the EEC module (A15). The solenoid valve interrupts the air supply to the exhaust device until the HEGO sensor (Lambda probe, BZ) has reached its operating temperature, under certain conditions (high lower suction pressure, high load).



The EVR/EGR solenoid valve (exhaust gas solenoid valve, Y33) controls the recirculation of exhaust gas quantities into the intake manifold. The valve is actuated by vacuum and is controlled by terminal 33 of the EEC module (A15). The EGR system does not function in traction mode or at full load.

Sensors

Terminal 46 of the EEC module (A15) is used as ground for the following sensors: exhaust gas pressure conversion sensor (B40), throttle position sensor (B8), HEGO sensor (Lambda probe, B3), coolant temperature sensor (B 10), camshaft position sensor (B41), intake air temperature sensor (B5), gear selector position sensor (B28), turbine speed sensor (B44) and gearbox oil temperature sensor (A40).

The exhaust gas pressure sensor (B40) and the throttle position sensor (B8) receive 5 V from terminal 26 of the EEC module (A15).

The exhaust gas pressure transducer sensor (B40) measures the pressure difference of the incoming exhaust gases and sends a signal to terminal 27 of the EEC module (A15). The sensor is part of the EGR system.

The throttle position sensor (B8) consists of a potentiometer built into the throttle valve, which sends a signal to terminal 47 of the EEC module (A15). With this signal, the module can calculate the position of the throttle valve (idle, partial or full load) and thus the fuel supply.

The HEGO sensor (Lambda probe, BZ) measures the amount of oxygen in the exhaust gas. A pulse signal is sent from the HEGO sensor (Lambda probe, BZ) to terminal 44 of the EEC module (A15). Thanks to this, the EEC module can adapt the fuel-air mixture for flawless operation of the catalytic converter.



The engine coolant temperature sensor (B10) (temperature-dependent resistance) receives its input voltage from terminal 7 of the EEC module (A15). The sensor informs the EEC module (A15) of the engine operating temperature, which is necessary for calculating the amount of fuel supplied.

The camshaft position sensor (B41) provides the EEC module with information about the starting position of the first cylinder via terminal 24. This information is necessary for opening the injection valves in the correct sequence.

The intake air temperature sensor (B5) transmits a signal proportional to the intake air temperature to terminal 25 of the EEC module. This information is used to calculate the amount of fuel supplied.

The vehicle speed sensor (VSS) (B11) transmits a square wave signal to terminal 3 of the EEC module (A15), the frequency of which is proportional to the vehicle speed.

The air quantity meter (B42) measures the amount of air that enters the engine through the air filter. This information is then sent to terminals 9 and 50 of the EEC module (A15) and is used to calculate the amount of fuel supplied.

The crankshaft position sensor (B43) transmits a signal about the crankshaft position to terminals 5 and 6 of the DIS module (A23). This information is used for proper timing control of the injector valves when starting the engine.

The article was taken in its entirety from the specified website: FordBook