Valve removal
The EGR valve is pressed into the intake/manifold.
To facilitate its replacement, it is best to remove the intake and exhaust manifolds.
Purpose of the exhaust gas recirculation system
Exhaust gas recirculation is used to reduce nitrogen oxides (NOx) in exhaust gases.
The injection ECU opens the exhaust gas bypass by giving a control signal to the system solenoid valve.
Principle of operation
The solenoid valve is controlled by a cyclic opening degree signal from the injection computer. The cyclic opening degree signal regulates the degree of valve opening, and hence the amount of exhaust gases directed to the intake manifold.
The ECU constantly checks the EGR flap position.
Working conditions
The activation of the EGR valve is determined by the following parameters:
- coolant temperature;
- air temperature;
- Atmosphere pressure;
- the position of the fuel control pedal;
- engine crankshaft speed.
- The exhaust gas recirculation system is disabled in the following cases:
- the battery voltage is below 9 V;
- at engine speeds below 700 min-1;
- one of the options (engine speed / load) above a certain threshold;
- vehicle speed below 12 km/h, engine speed below 1000 min-1, and the coolant temperature is above 60°C for 40 s.
The EGR valve is not energized after the engine is started for a period of time, depending on the current coolant temperature.
In the event of a malfunction:
- mass air flow sensor;
- pneumatic valve for exhaust gas recirculation;
- boost pressure sensor;
- boost pressure control solenoid valve, the EGR solenoid valve is de-energized.