Contents: Camshaft phase regulator 🠛 Control of the electric fan of the…🠛 Air conditioning compressor control 🠛 Fuel pump control 🠛 Oxygen sensor 🠛 Throttle body 🠛 Protection and switching unit 🠛 Accelerator pedal 🠛 Idle mode 🠛
The K4M and H4J engines are equipped with a TDC sensor for the first cylinder piston on the camshaft. Synchronization of control of the system elements with the engine operating process (determining the TDC of the piston of the 1st cylinder) is carried out by the signal of this sensor. The engine is started in a semi-sequential mode (to synchronize the control of system elements with the engine operating process), then switches to sequential synchronized mode.
On M4R engines, there is no TDC sensor for the first cylinder piston on the camshaft, so synchronization of the control of the system elements with the engine operating process is carried out according to the program using the TDC sensor signals. The engine is started in a semi-sequential mode (to synchronize the control of system elements with the engine operating process), then switches to sequential synchronized mode.
The injection system controls the illumination of three warning lights and the display of messages according to the severity of the detected faults in order to determine the necessary diagnostics.
The injection system ECU controls the activation of warning lights and the display of messages on the instrument panel. These warning lights come on during the engine start-up phase, as well as in the event of a fault in the injection system or engine overheating.
Commands to turn on the signal lamps are transmitted to the instrument panel via a multiplex network.
Camshaft phase regulator
The valve timing changes smoothly from 0 to 43° by the crankshaft rotation angle. The phase regulator is controlled by an electromagnetic valve, which is supplied with power in the form of a variable signal of the cyclic opening degree from the injection system ECU.
Control of the electric fan of the engine cooling system and the coolant temperature warning lamp
The request comes from the injection system ECU via the multiplex network (centralized coolant temperature control function). The supply voltage is supplied to the electric fan from the protection and switching unit.
Air conditioning compressor control
The request comes from the injection system ECU via the multiplex network. The request is generated based on the climate control system operation data, as well as the coolant temperature. The air conditioner compressor is powered via the protection and switching unit.
Fuel pump control
The request comes from the injection system ECU. The supply voltage is supplied to the fuel pump from the protection and switching unit.
Oxygen sensor
Two oxygen sensors are used, installed at the inlet and outlet of the catalytic converter.
Throttle body
Air supply and idle speed are controlled by a throttle valve with a servo drive.
Protection and switching unit
The unit supplies power to the following units:
- ignition coils;
- fuel pump;
- air conditioning compressor;
- electric fan;
- some actuators of the injection system (injectors, electromagnetic valve for purging the adsorber, etc.).
The protection and switching unit is located in the engine compartment next to the battery. The unit provides protection for the circuits of some electrical devices.
To perform this function, the unit includes fuses and several built-in relays:
- relay "+" after ignition switch;
- fuel pump relay;
- air conditioner compressor relay;
- engine Cooling Fan Relay;
- starter relay (starter traction relay control).
These relays are non-removable.
Accelerator pedal
The reference value for the engine ECU is the signal from the accelerator pedal sensor.
The sensor is made as a two-track potentiometer. The signal voltage from the sensor has two conductive tracks with different resistance.
From the first conductive track, a voltage (0-5 V) is supplied that is twice as high as the signal voltage from the second track (0-2.5 V).
Comparing the voltage of both signals allows you to ensure that the generated signal corresponds to the current value.
Idle mode
Idle speed increases by no more than 160 rpm if the battery voltage is below 12.7 V.
In case of a present and stored fault of the absolute pressure sensor, the specified idle mode is set equal to:
- 896 rpm (k4M engine),
- 1024 rpm (engines H4J, M4R).