Instructions. The EGR system is controlled by the engine control unit via the EGR valve "N18" to the mechanical EGR valve. EGR is switched off at idle speed after approximately 2 minutes. To further improve the EGR parameters, the EGR system is equipped with a radiator through which the coolant flows. The flow of recirculated EGR into the combustion chamber passes through this radiator. Thus, the EGR temperature can be reduced, which in turn reduces the temperature in the combustion chamber and leads to improved EGR parameters.
Exhaust gas recirculation system (aTL engines):
1. Nut. 22 Nm
2. Bolt 20 Nm
3. EGR radiator
4. Heat shield mounting clip
5. Heat shield
6. Intake manifold
7. O-ring. Replace
8. Mechanical EGR valve. Check
9. O-ring. Replace
10. Bolt. 10 Nm
11. Intake manifold fitting with intake manifold flap motor "VI57"
12. Bolt. 10 Nm
13. Suction pipe gasket. Replace. Mounting position: crossbar facing up
14. Bolt. 22 Nm
15. Gasket. Replace
16. Bolt. 22 Nm
17. Gasket. Replace
(Information obtained from this resource: «AUDIMANUAL.ru»)