Long distance driving , constant low revs = check engine light

[bennjamin]

Hi everyone.
Hit up a drive to Melbourne on the weekend - managed to do 600kms before the check engine light flicked on. No issue, car ran fine and the light disappeared after overnight.
Fuel economy sat on a decent 6.5-7l/100kms.
Noted was constant 2,500+/- rpm for a good 4-5-600kms , and very low temperatures (outside -2 to 2 or 3 degrees C)

Google tells me this is a " O2 sensor under load threshold" code or to that effect- it happened on the way down and way up.

Is this something to worry about ( replace 02 sensor) or is this completely normal ?

I worry, as I will be installing a DP and tune soonish.

[5pot]

It'll help if you tell us what car it is you have, exactly

[bennjamin]

2006 mkv golf gti :p

Dead standard , 95k kms.

[TomC]

I worry, as I will be installing a DP and tune soonish.

When you install a DP (with a high flow cat I assume?) you will need to have it written into your tune anyway. The increased flow will lead the stock tune to think the cat isn't working properly and will throw a code. Any good tuner should be able to write this into their tune, if you tell them beforehand that you have a DP.

[bennjamin]

good point - will do thanks.

But as for the o2 sensor - this minor issue isnt indicative of a faulty sensor , is it ? Or is it a generally acceptable issue with golfs lol ?

I guess the combo of cold cold weather , constant revs for along time sets it off.

[TomC]

My general understanding with cats is that they need to be heated to work properly. So as you say, if it's cold and there is a comparitvely low flow of exhaust gases going through for a large amount of time, I guess this could set it off...

[brad]

It would be fairly normal in many parts of Europe to have cold weather & long distances without a CEL.

I'd be investigating a bit further

[TomC]

Although it would be fair to say there would be more stop start wouldn't it due to more traffic, which would help to keep temps up? And on the faster pace on the autobarns would mean more exhaust gases also?

It would be fairly normal in many parts of Europe to have cold weather & long distances without a CEL.

I'd be investigating a bit further

[thezoneR32]

Really need to check this with VCDS.

[brad]

Although it would be fair to say there would be more stop start wouldn't it due to more traffic, which would help to keep temps up? And on the faster pace on the autobarns would mean more exhaust gases also?

Plenty of motorways & autobahns in Europe / UK where you have no choice but to go "slow".

I once drove from Weiz (near Graz) to the Swiss border & we didn't crack 100kmh the whole way because of weather, roadworks & traffic density.

[TomC]

we didn't crack 100kmh the whole way because of weather, roadworks & traffic density.

And because of this I assume you slowed down, accelerated, slowed down, accelerated and so on? With this type of driving, the constant accelerating would have kept exhaust gases and hence cat temps up wouldn't it have?

[bennjamin]

likely my car sat in a sweet spot for an issue on a 90,000km o2 sensor lol

- 2500rpm , 110-120km/h and below zero indicated outside temperatures all for 3+ hours.

[brad]

And because of this I assume you slowed down, accelerated, slowed down, accelerated and so on? With this type of driving, the constant accelerating would have kept exhaust gases and hence cat temps up wouldn't it have?

It felt like one long grind all the way.

Many European drivers aren't all that interested in going as fast as possible. The ones that I know were more interested in getting as much mileage out of their car as possible & tended to drive quite conservatively even if the autobahn was clear.

All I'm saying is that I don't think VWs are un-used to low temps & constant speeds around the 80-110kmh region.