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Model specific boards => Golf mk4 => Topic started by: ollyjg on 11 April 2013, 11:42

Title: Exhaust Emissions Warning Light
Post by: ollyjg on 11 April 2013, 11:42
Hi guys! This is my first post so bare with me! :)

I bought my first ever golf yesterday morning; and its a Y Reg GTi 2.0 (115). I drove it a whopping total of 25 miles before this light popped on. I dropped it into a garage who connected the diagnostics on it and codes come up; but we wasn't sure if some of the codes where from previous owner which hadn't been wiped so we got rid of them all, cleared the light and I drove away.

On my way back to uni last night the light come back on again. I'm a bit annoyed but after doing some reading into it it could either be the Lambda probe or MAF sensor? But my question is... the car has done very few miles in the year or so, less than 1500 or so. Is it possible that this light could of come on because it hasn't done many miles recently... and yesterday was its first proper run in ages?

While I'm at uni the car isn't going to be doing much, but when I head back home, if the light is still on and I am going to take it to a local garage and see what the problem is etc.

Thanks for all the help :)

Olly
Title: Re: Exhaust Emissions Warning Light
Post by: Metallix on 11 April 2013, 12:10

Certain emission fault codes require several conditions (e.g. speed/load/temperatures) to be met in order to run the test.  This type of fault code can be cleared, but once the conditions are met on a lengthy drive, the test will fail and a code will set.

Emission light requires the code to fail/set a number of times before the light will come on.


Seller may have known that the codes were there and that the light wouldn't come back on until you were far away.

Emmission faults could be numerous things, and for various reasons e.g. component aging, poisoned or damaged sensors/catalyst.

Best bet is to get a local independant garage to scan it for a small fee.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 11 April 2013, 12:44
Thanks for the reply!

Going to take it into a garage when I am back home and get them to scan it for me :)
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 13 April 2013, 10:19
Hi guys;

I've ordered a Talk to my car code reader that should be here today; when I get the error codes I'll post them up in here and see if anyone can give me a hand deciphering them  :rolleyes:

Also another quick question; I was looking at manually cleaning the MAF sensor and was just wondering how easy this actually is to do? I'm a relative newbie when it comes to working on cars; but the procedure doesn't look too difficult. Any advice would be greatly appreciated :D

Edit: Would this be a suitable spray to clean the sensor with? http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_195717_langId_-1_categoryId_255223
Title: Re: Exhaust Emissions Warning Light
Post by: beppe2672 on 13 April 2013, 16:46
Yeah
Mate that'll do the job, the only problem is the maf sensor is held in with anti tamper torq screws (like a regular torq bit with a hole in the middle) once out its just a case of giving it a couple of sprays, and leaving to dry.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 13 April 2013, 16:56
I used that spray and sprayed it just through the case; seems to have improved the general running of the car which is a plus.

Still have a rumble/judder of a sort that seems to almost 'pulse' through the car. Seems like its coming from the Catalytic convertor or the exhaust? Any ideas?
Title: Re: Exhaust Emissions Warning Light
Post by: brewey on 13 April 2013, 20:17
Just an idea but the rumbling feeling you keep getting on tick over could be from the throttle body, as I know mine was a little erratic before cleaning it. I know mine is the 1.8T but might be worth a try.

Remove your TB and then using some rag/ ear buds and carb cleaner get it nice and shiny as I imagine it will be black.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 13 April 2013, 20:45
Just an idea but the rumbling feeling you keep getting on tick over could be from the throttle body, as I know mine was a little erratic before cleaning it. I know mine is the 1.8T but might be worth a try.

Remove your TB and then using some rag/ ear buds and carb cleaner get it nice and shiny as I imagine it will be black.

Thanks for the suggestion! I will try this :)
Title: Re: Exhaust Emissions Warning Light
Post by: beppe2672 on 13 April 2013, 23:08
Could be worth checking your spark plugs too. That rumble could be a coil pack issue.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 13 April 2013, 23:25
Again, thanks for the suggestion!

I've been doing some reading up on TB cleaning.. and got a couple of questions;
1) Anyone got a link to a 'how to..' for a 2.0 gti model like mine? Been searching for agessssss and can't find any
2) do you need to disconnect the battery? Some how to.. seem to suggest you do, while others don't mention it?
3) Been reading about realignment and/or adaption.. I don't own VAGCOM nor do I know anyone with it.. is this necessary or will it sort itself out?
Title: Re: Exhaust Emissions Warning Light
Post by: brewey on 13 April 2013, 23:44
It will sort itself out eventually but could be between 20 and 100 miles maybe more. I didn't use vagcom to align mine and it was ok, but that doesn't mean it shouldn't be done.

Is yours DBW or cable? Sorry if its obvious but I don't own a 2.0l if it is DBW be careful not to move the butterfly valve forcefully as it is controlled by a stepper motor.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 14 April 2013, 00:04
It will sort itself out eventually but could be between 20 and 100 miles maybe more. I didn't use vagcom to align mine and it was ok, but that doesn't mean it shouldn't be done.

Is yours DBW or cable? Sorry if its obvious but I don't own a 2.0l if it is DBW be careful not to move the butterfly valve forcefully as it is controlled by a stepper motor.

I am a relative newbie when it comes to this; how would I find this out?
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 14 April 2013, 16:26
Just been outside to find my engine code and I'm pretty sure it's AQY?

Also I started her up and noticed quite a lot of black deposits being thrown out the exhaust, as well as some dark fumes. Could this explain my CEL and possibly hint towards Lambda sensor?
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 17 April 2013, 17:11
Anyone got a guide to getting at and checking coil packs on a 2.0 gti? Bit of a novice when it comes to cars...
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 19 April 2013, 14:05
Trying to keep this all in one thread  :grin:

So my little code reader came today and threw up these codes for me;

17536
Long term fuel trim system too rich (bank 1)
16518
02 Sensor Circuit - No Activity Detected (Bank 1 Sensor 1)
16555
Fuel Trim - System Lean (Bank 1)

Done a bit of reading around and people say its MAF, 02 sensor or ignition

Recently cleaned my MAF but had the light on before this, and my car has seemed to improved since the MAF clean so I wouldn't of thought it would be that..
So I'm guessing its the Lambda sensor that's causing all this? Any help would be much appreciated :)
Title: Re: Exhaust Emissions Warning Light
Post by: Metallix on 19 April 2013, 15:04
It says non activity on the lambda sensor, which either means its stuck / poisoned / not reading
OR you have fueling that is permanently stuck high or low.

I'd say change the lambda sensor.
Title: Re: Exhaust Emissions Warning Light
Post by: ollyjg on 19 April 2013, 16:35
is changing the sensor something that's easily done? Or does it require the car to go into a garage?