Engine Management System Sensors (BMW X5 E53)

The control system sensors are shown in Fig. 4.20.

Crankshaft speed sensor

The crankshaft speed sensor is mounted on the cylinder block above its pulley and is designed to determine the engine crankshaft speed for the injection subsystem, to generate a control signal for opening the injectors. It is based on the Hall effect and generates a pulse of one full revolution of the crankshaft, which is a reference signal for calculating the engine crankshaft speed and its instantaneous angular position.

Coolant temperature sensor

The coolant temperature sensor is a resistor with a negative temperature coefficient, meaning its resistance decreases as the temperature increases.

During engine warm-up, the ECU-KSUD enriches the fuel mixture based on an electrical signal from the temperature sensor installed in the cylinder head. If the engine does not start, starts with difficulty or stalls after starting, as well as with increased fuel consumption and CO content in the exhaust gas, it is necessary to check the serviceability of the coolant temperature sensor.

Exhaust oxygen concentration sensor

The oxygen concentration sensors in the exhaust gas are installed in a complex with a triple-action catalytic converter. There are four of them, two for each row, they provide feedback between the process of complete combustion of fuel and the ECU-KSUD, according to the reading of residual oxygen in the exhaust gas. From the oxygen concentration sensor in the exhaust gas (oxygen sensor) control signals are generated to maintain the optimal composition of the fuel-air mixture, close to stoichiometric.