ECU
The ECU is the main unit of the engine management system. It controls the fuel injection system and emission control systems.
The ECU receives signals from sensors that monitor changing engine operating conditions such as intake air temperature, coolant temperature, crankshaft speed, accelerator pedal position, etc. These signals are used by the ECU to determine the optimal amount of fuel supplied by the fuel pump.
Removing
Disconnect the negative battery terminal before removing any of the fuel system components.
1. Remove the ECU cover.
2. Disconnect the electrical connector by first lifting the locking lever at the top of the connector.
3. Remove the connector from the rear, disconnect the front and remove the ECU from the pins.
4. Lift the ECU up and remove it from the box.
5. Turn the fuel pump wiring connector on the top of the box clockwise.
6. Unhook the fastening lug using a screwdriver, then turn the connector counterclockwise and lift up.
7. Unscrew the two screws securing the wiring connector base to the unit box and lift the connector base.
8. Unscrew the inner and outer mounting bolts.
9. Remove the block box.
Installation
Installation is made in sequence, return to removal.
RPM and crankshaft position sensor
This is an inductive pulse generator, bolted to the clutch housing and creating pulses when jumpers pass between the holes in the flywheel near it.
When passing each jumper, one pulse is generated near the sensor, by which the ECU determines the crankshaft speed. One of the jumpers between the two holes is missing, and by skipping one signal, the ECU determines the position of the crankshaft.
Removing
1. Trace the wiring from the sensor to the wiring connector and disconnect it from the main harness.
2. Remove the rubber sealing ring, unscrew the bolts and remove the sensor from the crankcase.
Installation
Installation is made in sequence, return to removal.
Coolant temperature sensor
The coolant temperature sensor is an NTC thermistor, meaning that as the temperature of the sensor increases, its resistance decreases.
Intake air temperature sensor
The supply air temperature sensor is an NTC thermistor, meaning that as the temperature of the sensor increases, its resistance decreases. It is also used to correct the amount of fuel supplied.
Removing
Disconnect the electrical connector from the sensor and unscrew the sensor from the intake piping at the front of the engine.
Installation
Installation is made in sequence, return to removal.
Accelerator pedal position sensor
Information about the position of the accelerator pedal is transmitted to the ECU by this sensor. The accelerator cable is connected to a pedal position sensor, which converts pedal movement into an electrical signal. After processing this signal and using information received from other sensors, the ECU controls the high pressure fuel pump electronically so that the optimal amount of fuel is supplied to obtain the desired driving dynamics.
Removing
1. Remove the accelerator cable from the lever on the accelerator pedal position sensor located on the left front side of the engine compartment.
2. Remove the accelerator cable sheath from the O-ring in the sensor hanger.
3. Disconnect the electrical connector, unscrew the mounting bolts and remove the sensor with its suspension. If it is necessary to remove the sensor from the installation hanger, mark the position of the sensor relative to the hanger, then unscrew the two screws and remove the sensor.
Installation
Installation is made in sequence, return to removal.
Intake manifold pressure sensor
The pressure sensor measures intake manifold vacuum and feeds the information to the ECU to calculate engine load at any accelerator pedal position.
The sensor may be mounted at the bottom of the air filter or elsewhere in the front left side of the engine compartment.
Removing
1. Remove the vacuum hose and electrical connector and unscrew the two sensor mounting bolts.
2. Remove the sensor from its socket.
Installation
Installation is made in sequence, return to removal.
Nozzle needle lift sensor
The injector needle lift sensor is an integral part of one of the fuel injectors that sends a signal to the ECU when the injector opens.
Vehicle speed sensor
The vehicle speed sensor consists of a converter included in the speedometer drive. The ECU uses sensor signals to change the amount of fuel supplied according to vehicle speed.
Preheating control unit
This is an ECU controlled relay that connects the preheat glow plugs to the ECU for a certain amount of time when starting a cold engine.
EGR valve
The return of part of the exhaust gases to the intake manifold is controlled by the ECU in combination with a solenoid valve and an EGR valve. Vacuum from the vacuum pump is directed to the EGR valve through the solenoid valve according to engine speed, load and altitude.
Examination
1. If a malfunction occurs in the system, check that all electrical connectors are connected and not oxidized. Check that the air filter element is clean, the compression pressure in the engine cylinders is within normal limits and the engine ventilation hoses are not damaged.
2. If outwardly everything is in order, and there is a malfunction in the system, it is necessary to check the fuel system at a Peugeot station.