VW Engine Managment System warning light

campervan

Hi,

My 2001 beetle has the engine management light (or exhaust emissions light as it says in the manual)on constantly, been like this for some time now. However it passed the NCT recently, it also has a new timing belt and breather pipe and service as of 2 months ago. It’s been checked twice by VW and by my mechanic on a diagnostic machine and all the work that was to be done has been done. It sometimes stutters, chugs, jerks, don’t know what other way to describe it, in 3rd-5th gear, as if it is losing power, or struggling to stay in top gear. Could these two be related? Thought it might be catalytic convertor either.
My mechanic said if the light came back on after timing belt was done, he didnt know what else it could be. So after a week or so, it did come back on. I’m baffled and so is he, and I'm not sure where to turn with it. Thought someone might have an idea, any help appreciated. Its 1.6L and has done 80000 miles. Maybe I’m just a bad driver

p.s billygoatgruff and riskymove sorry if you think this is too much of a simple question for you guys, if you keep yawning u may want to hit the hay for a while. And I’m a gal by the way :rolleyes:

crosstownk

If it's been hooked up to a diagnostic machine and no faults have been recorded then that's somewhat unusual.

But you do seem to indicate that the light went out for a period after the timing belt was done. To be honest it sounds like it needs a more competent diagnosis. If the fault light is on then a fault should be stored in the fault memory. If possible can you get the exact fault that was recorded and post it here?

melbourne

Had a similar fault in my polo, turned out to be the airflow meter. Car used to idle unevenly and loose power at the top end or when pulling up inclines. Seems to be a regular fault as it also happened on an 04 polo we have. Little yellow light comes, fault in book refers to exhaust emissions I think. Maybe you mechanic is not too familiar with VW problems.

Car Mad

could be a lamber sensor that would throw on an engine light fairly expensive little f er to replace too.Did you bring it to a main dealer to have diagnostic check done because its should show up especaily if light is on in the dash.

Mr.Diagnostic

As was said above, if the management light is on then there will probably be a fault code stored. I say probably because it is possible for other systems to cause the engine light to come on. This is very rare though. The fact that there is an actual running concern would suggest that there is a problem with the EMS and as such I would be very surprised if there was not a fault code present.

Most people who are involved in “diagnostics” rely on fault codes to point them to a fix. This is true of both main dealer and independent techs. The fact is that a fault code is never any more that a clue to what the fault is and is often a red herring.

In cases like this the diagnosis needs to be a lot deeper than code reading and part swapping. It is possible to check and measure the various components of the EMS.

It is easier to find something like this if the system can be tested while the fault is actually occurring. Does the fault occur often?

campervan

thanks for replies

crosstownk - I dont think I have access to the fault unless I ask the mechanic about it. Although I'd be interested in getting one of those VAG-COM things Ive heard about and see for myself! The light was out for a few days then on and off, then on the whole time.

melbourne - the air flow meter was done recently too as far as I remember. and it does idle a but funny too, it can rev all by itself. the mechanic is an allrounder so I suppose he doesnt specialise in VW, trustworthy type though

car mad - yep brought it first to main dealer in Navan who said it wouldnt pass the NCT as it was and it did! apart from a parking bulb. they gave me a list of stuff that needed to be done so brought that to local mech and he did everything.

mr.diagnostic - i wonder are there mechanics anymore who dont work with computers?! it would be ideal to get it looked at deeper, but I cant imagine a VW dealer doing it, nobody knows of any VW specialists? Maybe its a longshot.
You know that Westward place in Enfield...they seem to do diagnostic faults. yes the light is always on, so the fault seems to be there constantly

Darragh29

Mr.Diagnostic wrote: »

As was said above, if the management light is on then there will probably be a fault code stored. I say probably because it is possible for other systems to cause the engine light to come on. This is very rare though. The fact that there is an actual running concern would suggest that there is a problem with the EMS and as such I would be very surprised if there was not a fault code present.

Most people who are involved in “diagnostics” rely on fault codes to point them to a fix. This is true of both main dealer and independent techs. The fact is that a fault code is never any more that a clue to what the fault is and is often a red herring.

In cases like this the diagnosis needs to be a lot deeper than code reading and part swapping. It is possible to check and measure the various components of the EMS.

It is easier to find something like this if the system can be tested while the fault is actually occurring. Does the fault occur often?

I recently had a Mitsubishi Pajero that had an ABS fault light on because a brake light bulb had blown, so it can happen... Bring it to somone who knows what they are talking about, if the engine management light is on, it's on for a reason.

Car Mad

campervan wrote: »

thanks for replies



car mad - yep brought it first to main dealer in Navan who said it wouldnt pass the NCT as it was and it did! apart from a parking bulb. they gave me a list of stuff that needed to be done so brought that to local mech and he did everything.

mr.diagnostic - i wonder are there mechanics anymore who dont work with computers?! it would be ideal to get it looked at deeper, but I cant imagine a VW dealer doing it, nobody knows of any VW specialists? Maybe its a longshot.
You know that Westward place in Enfield...they seem to do diagnostic faults. yes the light is always on, so the fault seems to be there constantly

A ha if the bulb was replaced lately i may know your problem.Sometimes when you replace a bulb in vws and it not done properly (for what ever reason)ahem *coughs cowboy mechanics it can throw on an engine light iv seen it happen the odd time something to do with a short in the wires.Sometimes changing the bulb again may fix the problem.Could be your problem if nothing shows up on diagnostics worth a try.No mechanics these days without a computer and with all these electrics they are badly needed:rolleyes: Even if they dont work at times.Shouldnt of passed the nct with an engine light on neither just gos to show how good are chief car safety inspectors are:eek:

Darragh29

Car Mad wrote: »

A ha if the bulb was replaced lately i may know your problem.Sometimes when you replace a bulb in vws and it not done properly (for what ever reason)ahem *coughs cowboy mechanics it can throw on an engine light iv seen it happen the odd time something to do with a short in the wires.Sometimes changing the bulb again may fix the problem.Could be your problem if nothing shows up on diagnostics worth a try.No mechanics these days without a computer and with all these electrics they are badly needed:rolleyes: Even if they dont work at times.Shouldnt of passed the nct with an engine light on neither just gos to show how good are chief car safety inspectors are:eek:

Engine fault light on is not an NCT fail item and never has been as far as I know... The exception is if the light being on is caused by a lambda sensor which might also be causing an emissions issue or unstable RPM idle issues...

Car Mad

Darragh29 wrote: »

Engine fault light on is not an NCT fail item and never has been as far as I know... The exception is if the light being on is caused by a lambda sensor which might also be causing an emissions issue or unstable RPM idle issues...

From what i always understood is if there was any warning light on in the dash it ment a fail could be wrong.Well the nct would rule out the lamba sensor not working as it wasnt high on emissions.My advice would be to check bulbs if they were replaced as i have seen it throw on engine lights a few times.I would also get a mechanic to check the egr valve for dirt and grit as they become blocked very easy in vws if its blocked get them to take it out and clean it with some carburettor cleaner and put it back in.Small enough job done it many a time in the glory days:pac: Also have a look under the bonnet for any pipes that may have come loose that a mechanic might not have seen very easy to miss a disconnected pipe if it bearly off or even a bit lose.

Darragh29

Car Mad wrote: »

From what i always understood is if there was any warning light on in the dash it ment a fail could be wrong.

Nope.

Mr.Diagnostic

campervan wrote: »

mr.diagnostic - i wonder are there mechanics anymore who dont work with computers?! it would be ideal to get it looked at deeper, but I cant imagine a VW dealer doing it, nobody knows of any VW specialists? Maybe its a longshot.

From what you have posted it would seem that the fault in you car is intermittent. The symptom that you mentioned “sometimes stutters, chugs, jerks” is almost certainly a direct result of the fault. The fact that it passed the NCT emissions would suggest the fault was not present at the time.
In fairness to the people who have looked at it already an intermittent fault can be very difficult to find. It is in situations like this that the average mechanic who does some diagnostic work can lose out. What you need is a diagnostic specialist.
Just to explain, a fault can cause the warning light but the light can continue to show even if the fault is not present.
Testing while the fault is not present can be difficult but not always impossible. Sometimes it is possible to see data parameters that are slightly out of range.

Not having seen the car this is just a guess but I imagine the issue of there not being a fault code present is a non issue. The answer to that is likely to be that there is a code but that it does not make sense to the techs who looked at it.

How often do you feel the symptom?
Where are you based?
If you are anywhere near Kildare I will plug in and read the codes for you.

mocarr

hi i have a 02 vw bora

recently the oil light came on (an orange light) so i put a ltr of oilf in, however today i was driving the car and the rph wnt from 40 to 0 , the oil light went red and back to orange and the engine management light came on. have i done some damage to the car? :(i have got someone comming to put more oil in and its booked fro a service this week. its a 1.4 petrol.... any answers would be great

wayne0308

I had this light come on in my Polo. I had it hooked up to the VAG-COM and no error codes recorded.

It turned out that my brake light switch was going. That's all it was very strange.

Basically my brake lights worked 80% of the time so when I used to check my brake lights the looked like they were working fine. I only noticed it when one night I pressed the brakes and they didn't come on but the next time I pressed the pedal they did.

The engine managment light seems to be a catch all on some cars. Hope you find out what it was soon, as I know how expensive it can get to find the fault some times.

Gary ITR

mocarr wrote: »

hi i have a 02 vw bora

recently the oil light came on (an orange light) so i put a ltr of oilf in, however today i was driving the car and the rph wnt from 40 to 0 , the oil light went red and back to orange and the engine management light came on. have i done some damage to the car? :(i have got someone comming to put more oil in and its booked fro a service this week. its a 1.4 petrol.... any answers would be great

Hi and welcome to boards. Bumping two year old threads is frowned upon, just start a new one, you will get better answers that way