Catalytic Converter Warning Light

[Jon1952]

This light has just come on on my 2010 TSI160 with 38K miles. This is the first problem I've had with it in over four years. So far it is the best car I've had (and I had many company cars before I retired including Audi and BMW)

Anyway I checked the internet and read some posts on here. I purchased a U 281 Code Scanner from Amazon to look for the fault codes. The engine etc read NO CODES but It got to the A/T (what's that?) and it said "linking error" but I used the erase option anyway and next time I started the engine the light went out. Now about 50% of the time when I start up the light stays on and I can reset it again using the coder. The light never comes on when I'm running.

I noticed that when the light first came on that the engine had been misfiring slightly on first start up but within 30 secs it was fine and ran perfectly smoothly when out on the road. I'm particularly sensitive about misfiring in view of what I've read about this engine. This uneven running on startup has occasionally happened before and then sorted itself out. This time I went for a blast down the motorway and it seems to have cured itself but the Cat light still comes on now and then.

I am reluctant to take it to the VW garage just yet. I had a similar light problem with a Mondeo a few years ago and it went in and out of several Ford garages without them ever fixing it. I think they just reset it and gave me a different story each time. (I'm a retired marine engineer so have some technical knowledge!) In those days I didn't have to foot the bill!

Any thoughts on this? How much do VW charge these days for a diagnostic check? If it looks like a faulty sensor how much are they to change to renew it?

Thanks for any help.

[Cuprabob]

The light is probably coming on due to the misfire. The lambda detects the unburnt fuel and flags a light to protect the cat as the precious materials can be damaged if unburnt fuel is continually dumped down the exhaust.

It may simply a coilpack.on the way out but as yoy say there have been many issues with the 1.4 TSI engines and misfires, some ofvwhich have required engine rebuild or replacements. Based on this, I wouldn't take any risks and take it to a VW dealer ASAP.

VW normally charge about 1 hours labour for diagnostics.

[Jon1952]

Many thanks for your advice. It has also occurred to me that I have just moved house and have been filling up with supermarket petrol for the last month rather than alternating with Shell as before. I will put in a tankful of V Power and see what happens. I tried V Power when the car was new but did not notice any difference in power or fuel consumption. Currently the engine is running smoothly but the cat warning light comes on about every 3rd time when I start it up and I reset it with the diagnostic reader.

[Jon1952]

Just to follow this up. I took the car in to the VW garage on Tuesday. They identified a fault on the N 80 Solenoid valve intake manifold. The valve was replaced and the fault has cleared. Total cost £194.45. Excellent service from my local VW dealer who took my car in immediately and let me have a loan car for the day and a half that they had my car. I just hope that it is now repaired.

[Cuprabob]

Good to hear:-)

[ChrisL]

Had same issue last week but mine is a 2.0 TDI @ 20 k miles. Dealer reset the Exhaust Gas Re-circulation (EGR) and the (stored) fault cleared and said if light returns then replace EGR under warranty. Useful background info here: http://www.myturbodiesel.com/wiki/egr-s ... -audi-tdi/" onclick="window.open(this.href);return false;

[ChrisL]

Follow up; my Cat converter light came back on so it's back to the dealers. Weirdly the low pressure tyre warning light also came on 10 minutes later and yet the tyre pressure were fine when measured with gauge. That sequence has repeated itself twice.

[ChrisL]

Follow up: EGR valve now replaced under warranty by the dealer.

[Rawcpoppa]

What's the part number for the EGR valve?

[ChrisL]

I wouldn't know, as the Dealer sorted it.