Need Advice Re: Check Engine Light

[Vr6boi]

I drive a 96 Jetta GLX VR6,my check engine light has been on forever...I get it checked..then they turn it off..but after awhile it just keeps coming on...had the oxygen sensors replaced...what could it be? has this happened to anyone else?
I did some research,seems like alot of mk3's have this problem..but the mechanics can't figure out why?
could it be the whole electrical system?
any info is appreciated...

thanks in advance!

[403Gemini]

there is a history of vw's with minor electrical problems. id say if the mechanics cant figure it out its probably something electrical.... however take it to a different shop and get a 2nd opinion would be my best answer. hope that helps

[RickDaTuner]

I would think its the MASS airflow Sensor they seem to be cause of many VW mystery problems,

dont take my word for it though as i am only speculating

[prosh]

Are you seeing any performance drops due to having the engine check light on? If not, then don't worry about it, it is probably something as dumb as having cheap gas in it :)

[Vr6boi]

It's been lagging alittle bit the last 6 months...
All oil changes are done on time,Always use premium 91
could be the mass airflow sensor...would this be due to a dirty air filter?

[GTS Jeff]

Originally posted by Vr6boi
It's been lagging alittle bit the last 6 months...
All oil changes are done on time,Always use premium 91
could be the mass airflow sensor...would this be due to a dirty air filter? that probably wouldnt trigger a cel, but its a good idea to get a new filter/clean it and spray some tb cleaner thru the system while hte filter is off.

[cobber112879]

SES lights may come on for many different reasons. Is it flashing? If so it will be a p0300 code indicating misfire. If not it could be anything. Did the shop tell you what the code was? If it's a MAF sensor fault the codes can range from MAF codes to LT & ST Fueltrim codes. If you can post the code I will PM you a diagnostic flow chart. :thumbsup:

[CalgaryB5]

Do you have Vag-Com? Or you can give Concept1 a call.

[Vr6boi]

Thanx for all the replys!

I did bring it into concept-1...misfire codes came up...they think it might be the knock sensor? (whatever that is) but they were all misfire codes...before I brought it into C-1 I brought it into northland VW..that was a big mistake :( scam artists.
Anyone know what the knock sensor does??
Probably sences vibration...maybe since my car ride is stiff,it causes my sensor to trigger...which then triggers my check engine light...

NO ONE SEEMS TO KNOW WHAT THE PROBLEM IS
:banghead:

kinda hesitant to bring it anywhere else...this problem is draining the flo...

[Vr6boi]

Cobber....NO it's not flashing.

Another thing,after I wash it sometimes.It starts but just bearly..when i give it gas..it kinda bogs (maybe due to too much water entering the engine/Steam) then this awful smell LOL comes from the exhaust,kinda sour:nut: .This doesn't happen often..but i'll like to know why? this is when the CHECK ENGINE LIGHT FIRST APPEARED.
The few time's this has happened..it stunk up the whole bigbucket carwash lol soooooooooo funny

[cobber112879]

Your knock sensor detects spark knock and signals your PCM to adjust ignition timing acordingly. They are kind of hard to driveway test. If you have a voltmeter you can plug that into the connector (AC Volts) and rap on the engine nearby the sensor with a wrench. You should get some sort of reading. A knock sensor is basically a set of piezoelectric crystals that produce a frequency or AC voltage when shaken. Cant really tell why your car stank so bad after washing.:dunno: If your knock sensor is faulty it MAY be signaling the PCM to retard ignition timing. This may lead to a noticible lack of power on low speed acceleration. Sorry, it's had to say what it could be without the code.

[Vr6boi]

thanks for the info...any good mechanics u could recommend? Let me rephrase. Any good, AFFORDABLE mechanics u could recommend that specialize in german carz?...Maybe i'll bring it back to C-1...their pretty good and their shop rates are alot less..with a problem like this,labour can skyrocket :( Anyways thanks again!