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Check engine light - frequency

Just wondering…as far as car dependability. How often would you expect a check engine light to come on with an 8 year old car if its a brand that has a good track record (Honda, Toyota, etc)? I know this is a pretty vague question but I have a VW GTI 2002 and the check engine light seems like its on more than its off at this point. Should I just deal with it at his point or trade it in and cut my losses? I just spent $900 two days ago on inspection and some other things (control arm bearings, cylinder coils, O2 sensor) now the check engine light comes on again this morning? Maybe its a VW thing?

VW dealers are not always the best as a whole. Where are you taking this car?

A VW versed mechanic can likely get you squared away.

The thing is all car makers have their quirks. An eight year old Honda has a high rate of failure with their automatic transmissions. Toyota has engines sludging around that time and plethora of other failures to this very day. Personally I would purchase a Toyota/ Honda or really ANY make on the promise of supposed reliability. Buy what suits and you like best and hope its dependable. Remember it is only a small subset of a all brands cars that have issues, the majority of cars sold are relatively trouble free however makes it.

Take the car back before you panic, it may or may not be related to recent work.

The CEL coming on may or may not be due to some of the repairs just done. Take the car back and tell them the CEL lit up after their repairs.

As Andrew said, look up and down for an INDEPENDENT shop that specializes in VW/Audi repairs. You stand a much better chance of getting your car fixed right the first time and most often somewhat cheaper than what a VW/Audi dealer will charge. Personally, I would rather park my 1986 8v GTI than take it to a dealer. Whatever I cannot fix myself, I take it to my trusted, independent VW/Audi shop.

Trading your car in just because the CEL in on, is akin to selling your house because you have a leaky kitchen faucet. You might want to consider taking your car to any major auto parts store (AutoZone, Oreilly, etc) and ask them to check for codes on your CEL; they will do this for free, and takes a few minutes at most. Make a note of the codes and post them here.

Your question is just sort of…well strange. The check engine light isn’t some kind of age or wear indicator, and isn’t something whose “frequency” tells you anything about the health of the car. The car’s computer just monitors major systems to keep track of performance and emissions items. This has nothing to do with car brand. The parts and systems that are monitored are pretty much standard across brands though there are variations, of course.

When your check engine light goes on take it to a national chain-type auto parts store such as Autozone. Ask them to pull your DTC codes - most do it for free. There are hundreds of these codes. Write down the code(s) that come out exactly as they are (e.g. P0123) then look up what the code means and what kinds of steps should be taken. You can also post them here for comment/advice.

As for the VW - I’d be hesitant to own one since there tend to be fairly high repair & maintenance costs associated. But your question of whether to keep it or not should have nothing whatsoever to do with the check engine light.

actually I did go to an independent repair shop that specializes in VW repairs and have been going to them for about 2 years. My annual repair/maintanence bill seems to be in the 1000-2000 dollar range lately. I actually have had better luck with them than with the dealer. But the amount of fault codes that my car has generated has been quite high over the past few years…probably somewhere between 10-20

I hear you about the rather high repair bills…Unfortunately, VW’s are not cheap to maintain and are below average when it comes to reliability. That being said, IMHO they are some of the most fun-to-drive cars. I also own a 1993 Honda Civic 2 door, which is absolutely soul-less, compared to the GTI. Ultimately it is up to you to decide if the higher cost of ownership of the VW is worth the joy derived from driving it.

For comparison my wifes 95 Taurus was bought new and traded in with 150,000 miles on it & the check engine light never came on.

Her 02 Sonata was also purchased new & has 153,000 miles on it & the CEL has never come on with it either.

There are 1000 reasons for a CEL to come on…So it’s not surprising motorists are observing them more and more often. As cars age, their emissions control systems deteriorate and the CEL nag light becomes more and more frequent. For $25-$35 you can buy a USB- OBD-2 interface cable and a simple program that will let you plug into your OBD-2 port and laptop and observe your cars engine control system at work…Read all the codes, reset the light, what fun! Talk about being distracted while driving. Better have the co-pilot play with the laptop…

I would expect it to come on anytime it detects a possible problem. We need to actual error code to do much more. It should be like “P1234” and any what did you pay $900.00 for. Note: VW has a few functions to their CEL system that can not be read by generic code readers. Most codes can be handled by the standard readers.

“How often would you expect a check engine light to come on with an 8 year old car if its a brand that has a good track record”

I would expect that it would not come on at all–on any well-maintained car.

My Outback, which is now 9+ years old, with 100k+ miles on it, has only had the CEL illuminate once, and that was due to an evaporative emissions solenoid valve that was defective, and was replaced under warranty when the car was a few months old.

After that incident, no CEL issues in the subsequent 8 years with this car.
And, none of my previous cars (representing GM, Ford, Honda, and Subaru) ever had the CEL light up in all of the years that I owned them.

As cigroller stated, the CEL only lights up when a problem is detected by the OBD2 system. Lax maintenance is the prime cause of the CEL glowing, although quirky transitory electronic issues or component failure may be involved in some cases.

My pair of Subaru’s that are 5yrs/85k and 6yrs/72k both have never had it turn on.

I suspect there’s a lot of story behind this car and the way the questions are phrased I don’t know how anyone can state whether this is a bad car or not.

The fact that have spent X amount of dollars per year and have had a CEL 10-20 times may not mean anything other than that you may have been spending money needlessly on wild guessing diagnostics. Without details no one knows but “frequency” is not the issue.

Mostly misfiring issues it seems. The air hoses have all been redone and this last time the cylinder coils and O2 sensor were replaced. The cost of the repairs haven’t just been related to the CEL so I don’t want to make it primarily a money issue…it’s just frustrating.

If most of this has been about misfiring issues then I’d say you basically need a new shop. Lots of people, some mechanics included, seem to think that the DTCs are these strange mysterious things that you make guesses about. Meanwhile, the “D” stands for “Diagnostic” and there are concrete diagnostic steps you take for various codes. If you keep having to go back with misfiring issues then these characters are not doing their jobs.

But ok is right. There is no way for anyone to tell much of anything without the full info & history.

Ok. First off, I have looked up the 4 codes from the last service.

Bank1: O2S (Lambda) Correction Behind Catalyst: Control Limit Reached : P1176
Random Misfire Detected -Any Cylinder or Random/Multiple Cylinder Misfire Detected:P0300
Cylinder #1 - Misfire Detected or Cylinder 1 Misfire Detected : P0301
Cylinder #2 - Misfire Detected or Cylinder 2 Misfire Detected : P0302

They replaced the O2 sensor and the cylinder 1&2 coil packs

The CEL came on 2 days later (as previously stated) so I bought a code reader for $30 (since each reading and resetting of the codes by my mechanic cost $42) and found this fault code:

Converter - Low Efficiency or Catalyst System Efficiency Below Threshold (Bank 1)

Any thoughts?

You’ve referenced coils and O2 sensors being replaced and unless I missed it have said nothing about spark plugs.
Many are under the impression that spark plugs are good for near infinity and the truth is that plugs can misfire to some degree even though the engine may appear to be running fine. Even the CEL may not be triggered by this.

Plug misfiring can also cause false O2 and converter codes. While the jury is still out on this, I will say that anyone who replaces coils without considering plugs, or even plug wires on models so equipped, is putting the cart before the horse.

I did see that spark plugs could be an issue with this code. I also saw that the o2 sensor could be an issue…which I just had replaced. But there are two O2 sensors? The other thing which I really don’t want to deal with is a replacement of the catalytic converter.

Ka-Ching! Ka-Ching! Ka-Ching!..

CEL’s are designed to remain off for the entire warranty period. After that, they can be expected to glow now and then as various plastic parts degrade with time. The Big Part(s) are the Catalytic Converters… Sounds like yours are nearing the end of their useful life…KAAaaaChing! One of our trusty Crown Vics, at 170K miles has started nagging me that my bank 2 converter’s efficiency is below threshold limits and would I please replace it. So far, I have not complied. I MIGHT spend $50 bucks on a new oxygen sensor and see if it likes the gasses it it is sniffing any better than the old one, or I might just use the $50 bucks to take my wife out to dinner…AND DRIVE ON !!

but how would you pass inspection?

The car is registered in rural Colorado…No inspections of any sort…

“Equal Protection Under The Law”…NOT! Some car owners are much more equal than others…

If I lived in an inspection area, I would restore a '70-'74 model Ford or Chevy, register it as a “classic” car and pollute at 100 times the level of the '98 Vic, legally, before I would submit to the insane CEL test failure nightmare…