Check Exhaust Warning Light

[ABTgolfer]

Hi guys,

I am a new owner of a used 2005 Golf GTI mk5 (WALD Edition) and I am all the way from Malaysia. I need some advise before I pop over to the workshop to have it checked. After a long distance drive yesterday, I was greeted by a Check Exhaust Warning light when I fired up my golf this morning. Can some kind soul out there tell me the possibilities of this warning? Faulty lambda sensor, etc..?

Cheers,
David

[Nasir]

Could be a lot of things, only VCDS can tell you for sure. Any other symptoms?

[ABTgolfer]

No...everything running fine as normal. I will pop by the workshop for a check but just need some possibilities before I get slaughtered by the workshops for no reason.

Cheers,
David

[no golf clubs at all]

I had this once before some time back, the light went off after about 20/30 miles or the next day.

[mclovin]

Had this on my car too. VCDS indicated that it was an intake manifold problem. Apparently this is caused by a variable "flap" not moving as it should and it was quickly resolved with an ECU software update. I'm not saying that your car has the same problem, just letting you know what happened with mine!

[ABTgolfer]

Checked and found the problem...Cycliner 2 is misfiring intermittently. From the VCDS, the checksum for misfiring on Cyclinder 2 keeps on increasing. Probably until a specific sum, warning light will come on and I notied, the ECU went into limp mode (reduction in power/boost).

So the next action is to find out what is causing the problem? Any help out there would be nice. According to ex-owner, both plugs and ignition coil was replaced recently. Mechanic suspected injectors...

Cheers,
David

[ABTgolfer]

Had this on my car too. VCDS indicated that it was an intake manifold problem. Apparently this is caused by a variable "flap" not moving as it should and it was quickly resolved with an ECU software update. I'm not saying that your car has the same problem, just letting you know what happened with mine!

Hi Mclovin,

Can you tell me more about the ECU update?

Cheers,
David

[mclovin]

Sure, not much to tell really. I got the check exhaust light popping up a few times, but it would disappear after a day or two.  VCDS identified fault code 004248 "Intake Manifold Tuning Valve Positioning Sensor (G336): Open or Short to Plus" and fault code 012600 "Intake Manifold Runner Control: Regulation Deviation". My dealer told me this was an ECU software issue and that an update would fix it, cost me £25 and had it done at the same time as the cam belt/DSG oil about two weeks ago. They said I would feel a difference as the car would take less time to start and feel faster under acceleration.

The car felt great after I picked it up which was great for a day or two but when I got my Bluefin map updated and put that on it was okay for maybe half a day and then I'm pretty sure the DV finally gave up as the car suddenly doesn't feel right at all and I can hear it hissing on-boost... Grr... New OEM Rev.D DV now ordered to fit at the weekend, so then everything should be back to normal and maybe I'll notice the difference this ECU software update has made!

[john_o]

According to ex-owner, both plugs and ignition coil was replaced recently. Mechanic suspected injectors...
Cheers,
David

Hi David,

theres not just one coil (with 4 HT leads to each cylinder) but one for each cylinder on the GTI.
(no need for long HT leads as they sit just above the spark plugs)
Its called a 'coilpack' and can fail.

So Id ask the previous owner if the 4 coilpacks were changed?

Easiest check is to swap coilpacks of the effected cylinder with one that ok.
That is swap no2 with no4 , then restart car and see in the problem 'jumps' to no4 in VCDS.

if it does then best to just change it for a new one.
(up to you  if you want to change all 4 coilpacks or just the one you know is a problem)

hope this helps
John

[ABTgolfer]

Hi John,

Changed all 4 coil packs yesterday. Car idle much better and no more misfiring on VCDS. But notice today that on start this morning, engine still sounded like a flat floor. Havent got time to the workshop to hook up to VCDS and......I suspect that my DV is dead. Hissing noise on boost and constant boost spike to 1.4bar. Any idea?

Cheers,
David

[john_o]

car shouldnt sound like a flat four, sounds like you still have other issues.
Is it still misfiring or just a very lumpy idle?

Id be checking for hoses that are not correctly fitted or leaking and that your exhaust is till connected fully and not blowing.
boost spike would be unusual if your DV is dead, usually its too little boost  (but it can be a common failure)
things like PCV can also effect the idle running so worth checking too.

For a 2005 car Id also be wanting to pull the HighPressure fuel pump to check the cam follower.

Im afraid logging in VCDS is the only way  to get the true picture, as you fix each issue as it comes up  
First to achieve no fault codes, then actually logging on the road values for boost/fuel pressure etc

If you were sold the car like this, Id be tempted to start from the basics and do things like a compressions test just to make sure the basics of the engine are healthy.

Its just a matter of going through things step wise, using facts from VCDS and looking at things that are common 2.o TFSI failure points.

hope this helps 

John

[ABTgolfer]

Hi guys,

My problem seems to be creeping back on me. Misfiring on Cyclinder 2 especially during cold startups. Changes all four coil packs, plugs, serviced my forged DV and swapped PCV with another GTI (workshop no stock). Anyone knows if a stcked charcaol canister will cause this?

Once engine is warmed up, misfiring will go away.

Cheers,
David