Vw Golf, Exhaust Emissions light

[mk5fsi]

Hi all,

These past couple days my car has developed a some what strange problem, 2 days ago my emissions warning light came on, on that same day coming back from uni the light came off again. And now yesterday morning it came on again... but this morning when i started it, the light didn't come on, so its sort of strange, the car is running perfectly fine. i'm not sure whether to take it in and get it checked, its sort of annoying, should i be concerned?

[Jmac]

If light has come on it will for sure have logged a code, and code could be any especially if its running ok, latest one i had like that was an intake runner that needed an adaption and there is actually a dealer software update if the adaption doesnt work but thats me runniing away abit, point im making is it could be anything so have it scanned.
Cheers
Jmac

[Getti]

If light has come on it will for sure have logged a code, and code could be any especially if its running ok, latest one i had like that was an intake runner that needed an adaption and there is actually a dealer software update if the adaption doesnt work but thats me runniing away abit, point im making is it could be anything so have it scanned.
Cheers
Jmac

My understanding was that it did not always log a fault. My engine light first came on about 12 months ago and has been to the dealer probably 6 times during that period. A sensor and 'carbon canister' has been replaced but has not fixed the problem yet. The dealer is unsure what the problem is after they scan the car and relies upon VW for guidance. The light has only today reappeared after the 'carbon canister' was replaced, so I have not yet contacted the dealer again.

The car is running completely normal, but it is more than frustrating and almost embarrassing regularly dropping the car off at the dealer.

[Jmac]

Pretty sure you will find when they scanned it , your car would have logged and Evap emission flow fault, reason for replacing canister. Yeah that would be frustrating and diagnosing them can be at times too.
Cheers
Jmac

[NabzGTI]

Do you get any smells of petrol inside the cabin? particularly at idol? The charcoal canister is to prevent fuel fumes from emitted into the atmosphere.

[mk5fsi]

Just an update, the light has not come on for the past 2 days, i might still take it in next week, to get it checked just to be on the safe side

[centralaxis]

Same thing happened to me a few weeks ago. Light came on when I started in the morning, but driving in the afternoon it went off after 5 mins. Took it to a mechanic to have it looked at, and it turned out that the battery was discharging and needed to be replaced... Makes sense, right?

But anyway, when you start the car up it goes through a systems check, and the emissions come before or after the battery check, so the battery was the issue, yet the emissions warning light came on.

Anyhow, hope your problem is an easy fix.

[Jmac]

Do you get any smells of petrol inside the cabin? particularly at idol? The charcoal canister is to prevent fuel fumes from emitted into the atmosphere.

Job along with the purge valve is to let fumes back into the intake if the 02 sensor requests it.
Jmac

[mk5fsi]

Hey guys, after being busy these last 2 weeks with uni, i have finally fixed the problem. I might as well add that the light didn't appear for 2 weeks and on Sunday it reappeared. Well yesterday i took it to my mechanic and it was a temperature sensor, he said that on earlier model FSI engines the sensors were a common fault. So i replaced the sensor and everything seemed fine, however on the way home, the engine cooked itself, lucky it was just outside my house. Anyway opened the bonnet, and all the coolant had leaked out from the reservoir tank and it was everywhere under the car. Called my mechanic he said he would come in the morning. So after 1hr, we found out that the temperature sensor clip wasn't pushed fully in, causing the leak. pushed it back in firmly, and it seems that it has stopped the leak, will monitor over the next couple days.

[mk5fsi]

Car has, no coolant leaks which is a good sign......However the exhaust emissions light has come on AGAIN!! The car as always runs perfectly. Will it ever stop coming on, I am tempted to just get rid of it. Any ideas to what could be triggering the light to come on?

[Mattautolec]

Coolant sensors are common but not for an emission light I wouldn't of thought.
Have you had the engine codes pulled recently?

[mk5fsi]

Hello everyone,

Car is finally fixed, turned out that the coolant sensor wasn't the issue. it was in fact the thermostat unit, so got that changed and the car hasn't had any problems.