Tip & How-To about Audi A4
An EGR valve usually fails prematurely due to a carbon build up within the inlet side of the engine. This means if you have a faulty EGR it is without doubt there will be an underlying cause.
You need to suss out what is causing the excess carbon build up in the first place. This, 9 times out of 10 will be the mass air flow sensor. It may still be within tolerance so that the EML (Orange light on dash with picture of an engine) is not emitted but be close to the end of it's working life. Live data is required to prove this but also beware of split hoses on the inlet side of the engine as they will also have a negative impact.
If the above faults are not rectified quickly the carbon will work it's way to the catalyst or DPF (Diesel Particulate Filter), these parts can be very expensive so act sooner rather than later.
Posted by Lloyd... on
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