Unsure about recently purchased new car


Hi there-

I just bought my first car. I bought a 2003 Jetta with 44K miles from used car dealership. As I was driving away (about 3 miles from the dealer) the check engine light came on. I immidiately brought it back to the dealership to have them fix it. I am pretty upset since i would not have bought this car if the light had gone on during my test drive.

The salesman told me that it is probably a lose gas cap, and not to worry, however, this seems unlikely since I didn’t even touch the gas cap.

have you guys heard this before? or have a really just bought a total dud of a car?

thanks for your info

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code not just their translation into English and post it back here. It likely will have a format like P1234. 

Then we will have a better guess about what is wrong and if the dealer needs a little push to fix something.


A loose gas cap can cause the Check Engine Light to go on. Easy excuse from a saleman that wants to blow you off or possibly it is what really happened. Get the code read as was suggested.


I guess that it is a little late to be asking this question but…Didn’t you have the car checked out by your mechanic prior to purchasing it?

Just for future reference, having an inspection performed by a competent mechanic is essential when buying a used car. If the seller doesn’t want to allow you to have it inspected by an independent mechanic, RUN from that dealer as fast as you can.

Since we can’t turn back the hands of the clock, however, at this point, you should do as was suggested and have the codes read by a place like Auto Zone, as that will give you accurate information regarding what you might be dealing with–be it a loose gas cap or another situation. After finding out the code(s), then take advantage of the warranty coverage that you received with this car, typically a 30 day warranty.


I’d like to say, “You’ll be fine,” because 1) millions of people are driving around today with their check engine light on, and 2) because you will. On the other hand, did you do your research on what used cars are the most reliable?


I just heard back from the service dept at the dealer and they said the code was PO420 which has to do with the catalytic converter. when they checked it out nothing seemed wrong with it, but he said that some highway driving would likely get rid of that warning. He thinks that it was caused by the car just sitting idle for a while.

sound like a reasonable story?

by the way- thank you for your input. i really don’t know much about cars and it is really nice to get valuable feedback from you folks!

thank you


Personally, I think the dealer is feeding you a line. Why not call an independent mechanic or VW dealer to ask them what the code means and what the standard remedy to fix the code is.


“He thinks that it was caused by the car just sitting idle for a while.”

I don’t buy his explanation. I would suggest, as was already suggested, asking the VW service dept. for their input on this issue.


“millions of people are driving around today with their check engine light on”

I hate to tell you this, but that does not convince me that it is desirable to drive around with one’s vehicle in that condition. When the CEL is illuminated, it is likely that the vehicle is putting out excess pollution, and/or getting poor gas mileage, and/or in the category of a vehicle that could soon be stranded by the side of the road.

There are also millions of people who are overweight, who have untreated illnesses, and who have substance abuse problems. Somehow, I don’t believe that these situations are healthy for people, and I also don’t think that driving a car with the CEL illuminated is an indication of a healthy vehicle. The OP should persist until that used car dealer makes her whole with this car.


Like VDC sez, I dont buy that either.

From the factory shop manual for my 02 Sonata:

"Code P-0420

Main catalyst efficiency deterioration

Probable cause:

Catalytic convertor deteriorated

NOTE: If any codes relating to HO2S sensor, MAF sensor, injectors,a P-O170 or a P-O173 are present, do all repairs associated with them before proceeding with this trouble area."

In other words if the only code coming up is the P-O420, the cat convertor is shot.

Like I said this is from the shop manual for my 02 Sonata, but the same -or very similiar-should apply to your V.W. also.

If the cat does need replaced, your’re covered 2 ways. Under the 30 day warranty from the dealer or under the 8 year/80K federal emissions warranty.

Did you buy the car from a V.W. dealer?


Tell them to put it in writing, then have another shop look it over. It could also just be something as an o2 sensor needing replaced, or it could really be a catalytic converter. Since the car is an '03 with less than 80k miles on it, you’re entitled to a federal warranty(not some dealership warranty) on the part if it really is bad.


Check with the VW dealer. The Federal warranty on catalytic converters is 8 years/80k miles. If the converter is bad then it will cost you nothing to repair.
The Feds say so.

What I would be curious about is why the converter failed at only 44k miles.


CEL’s can happen on any modern car (1996-present). It just indicates a fault in what the car considers normal operation.

Don’t worry that you bought a “dud”. If it happens future wise take it back to the used car dealer while under warranty if any. After find a trusty(non-dealer) mechanic, VW specific is helpful.

All cars have problems at some time in their life. Typically more as they age and accumulate mileage.

Enjoy your new car!


I think if the catalytic converter is fried because of some engine problem that was not addressed on time, then it would not be covered under the warranty.

The way I see this you have two problems, one is you need a new cat converter, but the more important one is to figure why this one has gone bad. I have had cars for many more miles than this VW and never had to change a cat converter.

Any chance you can change the car or return it? What is the conditions on the sales.