During operation, the controller processes information from sensors (crankshaft position, throttle, mass air flow, temperature, oxygen (lambda probe), detonation, speed) and - depending on the engine operating mode - issues control commands to the injectors, the ignition module, the idle speed controller, the canister purge valve, the fuel pump relay and the radiator fans.
The ignition timing is calculated by the controller depending on the crankshaft speed, engine load (mass air flow or throttle position), coolant temperature and the presence of detonation.
The composition of the mixture is regulated by the duration of the control pulse applied to the nozzles (the longer the pulse, the greater the fuel supply). Fuel can be supplied «synchronously» (depending on the position of the crankshaft, while the nozzles are switched on in pairs - for 1-4 and 2-3 cylinders) And «asynchronously» (all injectors work regardless of crankshaft position). The last mode is used when starting the engine.
If, when cranking the engine crankshaft with a starter, the throttle valve is open by more than 75%, the controller perceives the situation as a cylinder purge mode and does not output pulses to the injectors, cutting off the fuel supply. This is done if there is a suspicion that the mixture is over-enriched (engine «flooded») and therefore it does not ignite. If during the purge the engine starts to work, and its speed reaches 400 min–1, the controller will turn on the fuel supply.
When braking by the engine, the controller leans the mixture to reduce the toxicity of exhaust gases, and in some modes it completely turns off the fuel supply.
The fuel supply is also turned off when the ignition is turned off, which prevents the mixture from spontaneous ignition in the engine cylinders (dieseling).
When the supply voltage drops, the controller increases the energy accumulation time in the ignition coils (for reliable ignition of a combustible mixture) and injection pulse duration (to compensate for the increase in nozzle opening time). With an increase in the supply voltage, the energy accumulation time in the ignition coils and the duration of the pulse applied to the injectors decrease.
The control lamp of the engine management system in the instrument cluster informs the driver about malfunctions, but does not prohibit the further movement of the car. If the system is working, then when the ignition is turned on, the lamp lights up, but goes out immediately after starting the engine. If it lights up when the engine is running, there are malfunctions in the engine management system, the conditional codes of which the controller writes to memory (RAM). If the error disappears later (for example, contact has been restored in the sensor circuit), the lamp may go out; in this case, the fault code is not erased, but stored in memory and can be read using diagnostic equipment connected to the diagnostic connector located on the left under the instrument panel (close to relays and fuses). To erase the codes from the controller's memory, you must disconnect the battery for at least 10 seconds (or select the appropriate mode on the diagnostic tool).
Failure of some components of the injection system (electric fuel pump and its circuit, ignition module, spark plugs and high-voltage wires) is not detected by the controller and, accordingly, the control lamp of the engine management system does not light up. However, during interruptions in sparking, the control unit may issue an incorrect oxygen sensor signal code.