Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

How does the diesel EGR system work?

Model: (Various brands) Various
Part: EGR valve

Video tutorial

In this short video, we see the operation of the diesel EGR system with the role of the MAF sensor and the throttle valve: the MAF constantly measures the incoming air mass from the engine, while the throttle valve regulates the air flow. The ECU calculates the optimal amount of exhaust gas to be recirculated, controlling the opening of the EGR valve.

Inert exhaust gases are mixed with fresh air; the throttle valve is partially closed to create a vacuum, which helps the EGR gases enter the intake manifold. The MAF detects the reduction in fresh air, the ECU compensates by adjusting the throttle opening, the amount of EGR gas, and the diesel injection.

The result is the optimal mixture of air and EGR gas, lower combustion temperature, and reduction of NOx.


Posted on 30 October 2025 by ScegliAuto


Related tutorials

How to Clean the EGR Valve
How to Clean the EGR Valve
(Various brands) Various In this guide, learn how to clean the EGR valve using a specific product. When your diesel vehicle emits excessive fumes and the engine does not run …
What to do if we put dirty diesel in the tank of our diesel vehicle
What to do if we put dirty diesel in the tank of our diesel vehicle
(Various brands) Various Unfortunately, it can happen that dirty diesel fuel ends up in the tank of our diesel vehicle, meaning contaminated with water, sediments, bacteria o…
How does the EGR valve work?
How does the EGR valve work?
(Various brands) Various In this video, we are briefly explained how the EGR valve works: the part that controls the flow of exhaust gases is the actuator, which in this case…

Other guides you may be interested in

    Frequently Asked Questions

    • Vari - How much does the labor cost to replace the EGR valve? Read answer

How to Open the Fuel Flap on a Volkswagen Tiguan?

To open the fuel flap on a Volkswagen Tiguan, first unlock the car using the appropriate button on the remote. This will open the car and unlock the mechanism that controls the fuel flap. At this point, apply light pressure to the left side of the flap to open it and access the cap underneath. Once this is unscrewed, you can refuel and then close everything.

Watch the video!


by ScegliAuto

More videos