2006 Corsa warning light 23 October 2022 at 12:03PM in Motoring 3 replies 161 views

Sparkymark70

Hi folks. Had car pass MOT ok last week, however the yellow emmisions warning light has now come on & stayed on, had lot of rain last few days & someone mentioned water getting into exhaust could cause this ?

Goudy

The engine's ECU has detected an issue between air and fuel entering the engine and the make up of exhaust gases (too rich or lean).

Without knowing what the specific code stored in the ECU it's hard to know for sure what the actual problem is, but it could be one of a few things.
A few common ones are:
MAF or Mass Air Flow sensor is faulty.
A Lambda or O2 sensor in the exhaust is faulty.
Or the wiring to each of the above is faulty.
An air leak in the induction side after the MAF.
Leak in the exhaust or exhaust manifold. (owners can get a similar problem if they fit free flowing sporty exhausts).

You really need someone to read the ECU with a scan tool, get the diagnostic trouble code/s and more importantly understand what they mean to help fix it.

Sparkymark70

Update : scan done  & would seem to have been caused by MOT test dragging stuff through the Cat during emissions test. 

Goudy

What stuff?