Engine Light on but no OBD codes??

Hi,

Apologizes if this has been covered before, but I am looking at buying (another) A2, but the EML is on. Plugged in my low cost OBD reader expecting to find the problem, but "no codes" was reported! Went through the clear procedure just in case but the light is stubbornly staying on. It sounds like it is running fine and the person selling says it has been on for years but....

Has anyone seen this before??
 

2work

Admin Team
Evening Marcus,

I think the clue is within you’re text. The ‘low cost reader’ maybe your issue as it might not be able to identify the issue. If the light is on then something isn’t right.

It would help out if you added a location to your profile as someone, if near by, might assist scanning the car with VCDS whilst you’re viewing.

I’ve never used a generic reader before as have VCDS myself, which is the tools of choice for identifying fault codes. If you’re anywhere between Leicester and Lincoln I could swing by to scan for you free of charge.

Kind regards,

Tom
 
Hi,

Apologizes if this has been covered before, but I am looking at buying (another) A2, but the EML is on. Plugged in my low cost OBD reader expecting to find the problem, but "no codes" was reported! Went through the clear procedure just in case but the light is stubbornly staying on. It sounds like it is running fine and the person selling says it has been on for years but....

Has anyone seen this before??
What flavour of A2? Sounds like you need a VCDS scan
 
Hi Sorry, just seen your responses! Thanks for coming back to me with this.

The Car is located just outside Edinburgh so not so handy for Leicester area unfortunately, but I appreciate the offer!

The car is a 2004 TDI SE 150k.

I know the history of the car going back quite a few years as it is owned by the daughter of someone I work with. They previously bought it off a friend who is a mechanic who's wife drove it for many years. Apparently the light has always been on and the mechanic has also scanned and it reported no faults as well. His suggestion was it was a fault with the bulb / dash unit, but this sounds unlikely to me? ( I've heard of people tampering with them to turn the bulbs off but not on!)

Tempted to buy it with the light on anyway and take a chance - but the main problem is something else causes the light to come on it won't be seen...
 

PlasticMac

Member
Hi Sorry, just seen your responses! Thanks for coming back to me with this.

The Car is located just outside Edinburgh so not so handy for Leicester area unfortunately, but I appreciate the offer!

The car is a 2004 TDI SE 150k.

I know the history of the car going back quite a few years as it is owned by the daughter of someone I work with. They previously bought it off a friend who is a mechanic who's wife drove it for many years. Apparently the light has always been on and the mechanic has also scanned and it reported no faults as well. His suggestion was it was a fault with the bulb / dash unit, but this sounds unlikely to me? ( I've heard of people tampering with them to turn the bulbs off but not on!)

Tempted to buy it with the light on anyway and take a chance - but the main problem is something else causes the light to come on it won't be seen...
Has the car been scanned with VCDS specifically, or some other scan tool?
Many codes are VAG and engine specific, and may not be picked up by generic scans.
If VCDS doesn't pick up any codes, then like you, I'd suspect the dashpod.
Mac.
 

treblezero

A2OC Donor
My dash engine light has been on (occasionally off) for over a year now. Last service the mechanic scanned (proper kit) and identified a stuck valve or something, located in the manifold? Like a vent that should open and shut depending on the flow required... Anyway, it doesn't seem to have caused any adverse running issues and it does occasionally turn off. I wondered if it was due to short journeys and or been stood for long periods (often all week). so I've not dug any deeper. However, it would be good to know a little more and if this is a fault that could be detrimental to the engine if left unresolved
 

Catnip64

Member
My dash engine light has been on (occasionally off) for over a year now. Last service the mechanic scanned (proper kit) and identified a stuck valve or something, located in the manifold? Like a vent that should open and shut depending on the flow required... Anyway, it doesn't seem to have caused any adverse running issues and it does occasionally turn off. I wondered if it was due to short journeys and or been stood for long periods (often all week). so I've not dug any deeper. However, it would be good to know a little more and if this is a fault that could be detrimental to the engine if left unresolved
Depends which engine you have, if an FSI then the fix is a little more involved....
 

Catnip64

Member
1.4 TDI 2005
In that case it's probably the EGR valve which is sticking. It's worth cleaning the unit and checking to see if there's any oil in the controller mechanism or broken gear teeth. If you find any damage then repair kits are available, or a replacement unit could be fitted.
@depronman has a software fix to make the unit less sensitive if no mechanical problems are discovered.
 

treblezero

A2OC Donor
In that case it's probably the EGR valve which is sticking. It's worth cleaning the unit and checking to see if there's any oil in the controller mechanism or broken gear teeth. If you find any damage then repair kits are available, or a replacement unit could be fitted.
@depronman has a software fix to make the unit less sensitive if no mechanical problems are discovered.
I'm not great with acronyms, sorry. What is an EGR valve and where do I find it? Sounds like something I could tackle up at the lockup. Thanks
 

Proghound

Admin Team
I expanded the acronym in response to your post on another thread. I've never had to do anything with mine though so I'll have to let someone else help you with the 'where' and hopefully offer a 'how-to' as well.
 

depronman

Member
It is far more likely to be the ASV (anti shudder valve) than the EGR (exhaust gas recirculate) valve

As was already stated strip down the ASV and look for broken teeth and get a repair kit if any found
It is likely that the fault will still be present as the Audi engine map is a little too tight tolerance on the ASV
I have a fix for this but it involves modifications to the map stored in the engine ecu

Let me know if you need more details etc

Cheers. Paul


Sent from my iPhone using Tapatalk
 

treblezero

A2OC Donor
It is far more likely to be the ASV (anti shudder valve) than the EGR (exhaust gas recirculate) valve

As was already stated strip down the ASV and look for broken teeth and get a repair kit if any found
It is likely that the fault will still be present as the Audi engine map is a little too tight tolerance on the ASV
I have a fix for this but it involves modifications to the map stored in the engine ecu

Let me know if you need more details etc

Cheers. Paul


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Thanks for chipping in, Paul. Always appreciated. I'll see if I can manage a strip and clean. If it's accessible enough for someone with my level of mechanical experience (fair to middling - mostly analogue) can take on.
 

depronman

Member
It is easy to access as it is top rear of engine with a big black pipe going into it

Paul


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Un4tural

Member
just to throw it in, the generic OBD scanners do not pick up codes on the A2 at least ones I tried, not sure of other audi models, have a couple, they can pick up live data for rpm/airflow etc. but not fault codes.

obceleven does codes and resets them fine, so does vcds.
 

treblezero

A2OC Donor
just to throw it in, the generic OBD scanners do not pick up codes on the A2 at least ones I tried, not sure of other audi models, have a couple, they can pick up live data for rpm/airflow etc. but not fault codes.

obceleven does codes and resets them fine, so does vcds.
Thankfully, my local mechanic has the right kit to do the diagnostics and he's happy to run the odd test FOC. I bought a cheap older model OBD scanner once, as ye say, not much use.
 

Evoman

Member
It is far more likely to be the ASV (anti shudder valve) than the EGR (exhaust gas recirculate) valve

As was already stated strip down the ASV and look for broken teeth and get a repair kit if any found
It is likely that the fault will still be present as the Audi engine map is a little too tight tolerance on the ASV
I have a fix for this but it involves modifications to the map stored in the engine ecu

Let me know if you need more details etc

Cheers. Paul


Sent from my iPhone using Tapatalk
Hi Paul, just reviving this thread to ask about the repair kit you mentioned for the ASV - curious if there is somewhere you've sourced one of these kits from before? I've found upon inspection of my ASV after throwing a fault the small cog has some stripped teeth...
THanks!
 

depronman

Member
I’ve not had to do this as the teeth have always been ok but I do recall a member bought a set of gears from eBay


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