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Diagnosis and adjustment
Electronic engine management system consists of an electronic control unit and the following sensors:
- The throttle potentiometer - informs ECU on the throttle position and speed of the closing / opening of the throttle valve;
- Coolant temperature sensor - informs the control unit of the engine temperature;
- Air flow sensor - informs the control unit about the number and temperature of air passing through the air inlet duct;
- Sensor crank angle (set in the ignition distributor) - informs the control unit of the engine speed and the position of the crankshaft;
- Speed sensor (installed in the speedometer) - informs the control unit of the vehicle speed;
- The switch in the power steering control and switch the air conditioning system (if installed) - inform the control unit for the inclusion of these systems to the control unit could adjust the engine idle speed to compensate for the additional load on the engine from these systems;
- Emission sensor (only on models with catalytic converter) - the control unit sends information about the content of oxygen in the exhaust gases.
Signals from all of these sensors are analyzed electronic control unit. Based on this information, the electronic control unit regulates the fuel injectors (changing the pulse duration - the time period during which the injectors are open - in order to get a more rich or poor fuel mixture, depending on whether it is necessary). The composition of the fuel mixture and the engine idle speed is constantly changing electronic control unit in order to provide optimum engine start (at a cold or warm start), the engine warm, the engine idling, the best engine performance while driving on a highway and a sharp set speed.
Electronic engine control unit fully controls the speed of the engine idling through an additional air supply valve. This valve, which is mounted on the throttle body (models with engine capacity of 1.6 liters), or the intake manifold (models with engine capacity of 2.0 liters), controls the opening of the air duct, which runs past the throttle. When the throttle is closed, the electronic control unit controls the opening of a valve which regulates the amount of air passing through the throttle body bore, and thus is controlled by the speed of the engine during idling.
On models with the 1.6-liter engine throttle body has a device that can independently increase the speed of the engine at idle speed when the engine is warming up. This function is controlled by the temperature valve. When the engine is cold, the wax capsule in the valve (the valve is installed in the throttle body) is small, and a cam of fast idling keeps the throttle slightly open. When the engine is warming up, the wax capsule expands, raising up the valve plug, it is, in turn, rotates the cam fast idling to the desired position.
On models with the engine capacity of 2.0 liters increase idle speed is controlled by adjusting the air supply valve, which consists of a bimetallic spring and a damper. When the engine is cold, the bimetallic spring holds the valve open. The air passes through the valve, which increases the flow of air into the intake manifold. When the engine is running at a bimetallic spring valve is energized, which gradually increases its temperature. When the temperature increases, the bimetallic spring deforms and closes the valve, stopping the flow of additional air motor.
All models are also on the throttle body mounted solenoid valve to increase the speed of the engine at idle, which is controlled by an electronic control unit. The solenoid valve controls the opening of the air duct, which runs past the throttle valve and is used to increase the speed of the motor when the strengthening of a steering system or air conditioning.
A warning  On some models, the valve can be installed but will not function.
On models with a catalytic converter, electronic control unit also controls the exhaust system and a control system for the release of fuel vapors, which are described in the relevant chapter.
If the signals received by an electronic control unit from the sensors out of range, or inconsistent with each other, the electronic control unit switches to the protected mode. In this case, the electronic control unit ignores invalid sensor signals and receives sensor signals for a certain predetermined value, which will allow the engine to operate, albeit with reduced efficiency. If the electronic control unit switches to the protected mode, the instrument panel warning light comes on and the corresponding fault code is entered in the memory of the electronic control unit.
If the warning lamp lights up as soon as possible to address to experts. The garage can be carried out full diagnostics engine management system using electronic diagnostic equipment, which must be connected to a diagnostic socket.
A warning Electronic engine control unit also has a self-test mode, you can use the motorist. For more information, cm. Subsection 6.3.1.12.
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