check engine light and dirty air filter

CheesyRider

Well-known member
Joined
Jan 16, 2006
Location
White Bear Lake, MN
TDI
2010 Jetta SportWagen TDI
Hi! This is my first time ever posting on the TDI Club forum, so please forgive me if these questions have been asked before.

Okay, so here's the story:
Last week the check engine light on my 2002 Golf TDI went on. I called the dealer and was told to take the gas cap off, put it back on and drive the car for a few days to see if the check engine light would go off.

Well, two days later (with the check engine light still on), I took a short drive to the shopping mall (only about 3/4 mile, the temperature was 30 degrees). After spending about 2 hours at the mall, I tried to start the car. The engine would just turn over, but would not start. I wondered if the fuel filter could have been clogged, but I changed it myself just 3000 miles ago. I decided to leave the car there overnight and try the next day.

The next day (the temp was about 38 degrees) I tried to start the car again, but it still just turned over and wouldn't start, so I called a tow truck. Right before the tow truck arrived, I tried again, and the car started right up.

Even though the car seemed to be starting and running fine, the check engine light was still on, and I was worried about the car not starting again. I decided to call the dealer and bring it in so they could take a look at it. Just before I was about to leave, I decided to check the air filter (even though are supposed to check this at Quick Lube every time I get my oil changed). Sure enough, the air filter was filthy! I guess I shouldn't have trusted the Quick Lube guys.

I decided to replace the air filter and see if the check engine light would still come on. The engine light still went on, so I proceeded to go to the dealer.

When I arrived at the dealer and explained everything I mentioned above, the guy there thought that the dirty air filter was my problem all along. He went on to say that after 15 normal starts, the check engine light would reset itself if it was indeed the air filter.

So finally here are my questions:
Would a clogged air filter cause the check engine light to go on?
Would a clogged air filter cause the starting problems I described?
Is the dealer right that the engine light will reset itself after 15 normal starts if the new air filter soved the problem?

THANKS!!
 

hagar

Veteran Member
Joined
Sep 8, 2005
Location
Columbia, SC
TDI
2002 white Jetta 5sp & 2006 Mercedes CDI
So what kind of oil did they put in at QuickLube? Unless you know for sure, have them show you the container, watch them put it in, I would not trust them. If your air filter was clogged, chances are your MAF is dirty. Take it off and rinse it with a little bit of rubbing alcohol.
 

CheesyRider

Well-known member
Joined
Jan 16, 2006
Location
White Bear Lake, MN
TDI
2010 Jetta SportWagen TDI
hagar said:
So what kind of oil did they put in at QuickLube? Unless you know for sure, have them show you the container, watch them put it in, I would not trust them. If your air filter was clogged, chances are your MAF is dirty. Take it off and rinse it with a little bit of rubbing alcohol.
I bring my own synthetic 5w40 oil and oil filter to the QuickLube. I used to change the oil myself but they charge about 13 bucks for laber so I decided it wasn't worth doing it myself--at least until now. I guess that checklist they give me after every oil change is completely worthless! From now on I'm at least going to double check everything that is done on my car.

Thanks for the advice on the MAF! I'll go check that out right now.
 

TornadoRed

Top Post Dawg
Joined
Aug 3, 2003
Location
West Des Moines (formerly St Paul)
TDI
2003 Jetta TDI wagon, silver; 2003 Jetta TDI wagon, indigo blue; 2003 Golf GL 5-spd, red (PARTED); 2003 Golf GLS 5-spd, indigo blue (SOLD); 2003 Jetta TDI wagon, Candy White (SOLD)
CheesyRider said:
Last week the check engine light on my 2002 Golf TDI went on. I called the dealer and was told to take the gas cap off, put it back on and drive the car for a few days to see if the check engine light would go off.
This might work, if you had a gasoline engine. Idiots!

After spending about 2 hours at the mall, I tried to start the car. The engine would just turn over, but would not start.... Right before the tow truck arrived, I tried again, and the car started right up.
Check your anti-shudder valve. If it hadn't released by the next day, it could mean that your EGR valve and intake are clogged. But any time a warm engine doesn't start, check the anti-shudder valve first.

decided to check the air filter... Sure enough, the air filter was filthy! ... When I arrived at the dealer and explained everything I mentioned above, the guy there thought that the dirty air filter was my problem all along. He went on to say that after 15 normal starts, the check engine light would reset itself if it was indeed the air filter.
The guys at your dealership don't seem to want your money. At least they don't care to work on your car and find out what's really wrong. They don't want to clear the error code? The CEL will go out, but the error code will still be stored.

So finally here are my questions:
Would a clogged air filter cause the check engine light to go on? No
Would a clogged air filter cause the starting problems I described? Probably not
Is the dealer right that the engine light will reset itself after 15 normal starts if the new air filter soved the problem?It may reset itself, but not for the reason you were given.
A clean air filter and a clean MAF sensor may help. But don't be surprised if the CEL comes back on.
 
Last edited:

mparker326

Veteran Member
Joined
Feb 28, 2005
Location
Knoxville, TN
TDI
Golf 2002 Gray
Why don't you go by autozone and have your code read for free and post it here?

By the age of the car, I would guess it is a glow plug issue.
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
" Okay, so here's the story:
Last week the check engine light on my 2002 Golf TDI went on. I called the dealer and was told to take the gas cap off, put it back on and drive the car for a few days to see if the check engine light would go off."

I was told the same thing once. Dealers that say this are morons! That only applies to gasoline-powered cars. They have evaporative emissions systems and diesels do not. The evap system has a self diagnosis for leaks and if a test pressure can not be maintained the CEL comes on. Gasoline only though!:rolleyes:

--Nate
 

CheesyRider

Well-known member
Joined
Jan 16, 2006
Location
White Bear Lake, MN
TDI
2010 Jetta SportWagen TDI
mparker326 said:
Why don't you go by auto zone and have your code read for free and post it here?
I hate it when people post about a problem and never follow up with the solution. I happened to be browsing my old posts when I came across this one from 4 years ago. If my memory serves me correctly, I did go Auto Zone and the code was for a coolant sensor problem. I replaced the sensor and my check engine light went off. I give a belated thanks to everyone who replied to this thread! There, now I'm no longer one of those annoying people who doesn't follow up. Instead, I'm one of those annoying people who brings up a thread from four years ago.:p
 

CheesyRider

Well-known member
Joined
Jan 16, 2006
Location
White Bear Lake, MN
TDI
2010 Jetta SportWagen TDI
Thanks greengeeker! I hope I don't have to take you up on the offer for a long time, but I appreciate that you're available to help if needed.
 
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