Calling for help from the north east Midlands crew. Our mk2.5 has developed an unknown issue and the engine warning light has come on. However everything seems fine and it drives ok.
I have read various forum posts on this subject and there could be lots of reasons for the light coming on, bottom line is it needs to have its error codes read via obc port.
If the is anyone going to the coopers on Thursday night that has a obc reader and would be kind enough to read the error codes so I can get it fixed, it would be appreciated.
Happy to help, as am trying to track down (possibly) the same problem on my Mk2.5. Unfortunately, am away for the next two weeks. First question, is it a constant amber warning light? Second question, can you feel a problem with the engine performance (misfire, stutter etc…). On my car, it appears as a very intermittent misfire, after which the warning light comes on. From what I’ve read on the internet, as you say there are many reasons for this, but if you can’t feel the problem, don’t worry too much. The first thing to check is the plugs, then the HT cables. There are several posts on the internet stating that if you disconnect the battery for about half an hour, that will reset the code, then you can see when it reappears. This worked on mine and after several days, hey presto it reappeared. Let me know how it works out. If no OBDC connector available on Thursday, I have one and will be back in about two weeks, however all it told me was that I had a misfire!!!. D’oh.
No misfire and engine is running smoothly. Car was serviced 1 week ago, so I have checked all oils and fluids and all are good.
Tick over is smooth and not self reving I. E. Revs changing by themselves.
I’m guessing it’s a sensor or electrical issue, hence the need to read the odb port to see what error codes come back.
Colin has a reader that he has used and will bring it on Thursday night, so fingers crossed it may give me a steer in the right direction, otherwise it’s off the the garage
Ok, update for you all. Colin has checked the engine for the error code and it has come back as P0420
Now according to the Internet it’s the o2 sensor…
There are a number of things that could be causing this p0420 catalyst efficiency code. The most common thing is the catalytic converter itself is no longer functioning properly. The other likely thing is the rear O2 (oxygen) sensor is no longer working properly.
It’s going to the garage on Saturday so will update after that.
It’s been to the garage and they checked the sensors and they are working fine. However they then checked the emissions and they are all over the place, plus when you hit the CAT with a hammer you can hear it’s moving around inside… so it’s the CAT not working properly that is sending the emissions out of range and the sensors can’t compensate.
Sorry for the delay, however there’s a happy ending to this chain. I met the guys at GoPerform who have fitted a full stainless steel system with sports cat… IT’S FECKING AMAZING!! Sounds Great, looks Great, it’s brilliant!