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What are the symptoms of a faulty EGR valve?

Model: (Various brands) Various
Part: EGR valve

A faulty EGR valve can cause various problems, especially in diesel vehicles (but also in gasoline ones), including loss of power and overall poor performance, increased fuel consumption, difficulty starting, especially when cold; irregular idling, smoke coming from the exhaust: black for incomplete combustion, white or bluish for possible burned oil. Very often, the engine light also turns on, indicating an error such as P0401, P0403, or P0404. We might also hear strange noises, and in more severe cases, engine overheating. In many cases, the problem can be resolved with a thorough cleaning of the valve, or if it is broken or too clogged, with its replacement.

Posted on 25 January 2026 by ScegliAuto

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