EML light keep coming on but no fault code

Sylvester

Member
Hi, all just have a bit of issues with EML and 620 idle speed, not sure these 2 might be connected. I thought the new plugs and leads will solve these issues but they didnt.

When I bought the car 2-3 weeks ago, I was told EML light was on because throttle body needed cleaning. I was told that job was done, but to reset light you need to pay audi for it, so light is there but engine was okay.
I bought an OBD2 scanner, and with Torque app I actually managed to clean the EML off and was no fault codes.
All was good, but 2 days later the EML came on again. I checked ODB again, no fault codes, cleared EML.
Few days later EML came on again!! I've just checked it now, still no fault codes and just cleared EML again. I got a feeling that EML will come one again in a few days.
Any idea why is can't delete that for good?
Maybe something to do the the low 620 idle speed?
The new plugs and leads definitely made engine run smoother, but both issues still there. Thanks
 
Hi,

I think your app is not showing all the fault codes. The light will be on because there is an error stored which is why it goes out when your clear the stored fault memory. The symptoms sound like an additive fuel trim mixture too lean error, something like this:

17559 - Long Term Fuel Trim Additive Air; Bank 1; Range 1
P1151 - 35-00 - System too Lean

A scanner that is able to show everything that's going on will confirm what's going on.

If it is this, then you either have an induction air leak or insufficient fuel flow / poor injector spray.

regards

Andrew
 
Hi, all just have a bit of issues with EML and 620 idle speed, not sure these 2 might be connected. I thought the new plugs and leads will solve these issues but they didnt.

When I bought the car 2-3 weeks ago, I was told EML light was on because throttle body needed cleaning. I was told that job was done, but to reset light you need to pay audi for it, so light is there but engine was okay.
I bought an OBD2 scanner, and with Torque app I actually managed to clean the EML off and was no fault codes.
All was good, but 2 days later the EML came on again. I checked ODB again, no fault codes, cleared EML.
Few days later EML came on again!! I've just checked it now, still no fault codes and just cleared EML again. I got a feeling that EML will come one again in a few days.
Any idea why is can't delete that for good?
Maybe something to do the the low 620 idle speed?
The new plugs and leads definitely made engine run smoother, but both issues still there. Thanks
Glad to see you are are happy with your oil level in the other thread, welcome to the forum by the way, the 1.4 petrol is fairly reliable.

I have not got a petrol 1.4 so no specific help, more general comments.

I also have no knowledge of OBD II, apart from it seems respected, nor your Torque app, in fact I can offer little.

I do understand how the eml is on and no codes showing. I suppose there is a small chance that the ECU has a fault and throwing up the eml for no reason, but I think it is much more likely your diagnostic kit for whatever reason is not showing the codes.

You ask why does the eml keep coming back? The answer is easy as you cannot identify the fault you have not fixed it and the fault remains.

My advice is to get a VCDS scan, the bees knees of diagnostic kit for VAG cars, and you will see the fault codes and be able to set about fixings the fault which is causing the eml.

I am near Oxford, have full VCDS and happy to offer a scan, it only takes 5 minutes, but I am not is exactly local to you. There must be members far more local to you who will help, look in the diagnostic forum, and as a last resort make a general appeal for a local scan. Anybody in DORSET?

Andy
 
or just buy an ebay VAGCOM cable for £5 and away you go, you will need a laptop running nothing latter than windows 7 though
 
I had my EML light on recently, I think my throttle body and EGR valve are both bunged up,

I just went out and gave the car a good blast touching the red line every gear change and the light went off and hasn't come back.

John
 
Glad to see you are are happy with your oil level in the other thread, welcome to the forum by the way, the 1.4 petrol is fairly reliable.

I have not got a petrol 1.4 so no specific help, more general comments.

I also have no knowledge of OBD II, apart from it seems respected, nor your Torque app, in fact I can offer little.

I do understand how the eml is on and no codes showing. I suppose there is a small chance that the ECU has a fault and throwing up the eml for no reason, but I think it is much more likely your diagnostic kit for whatever reason is not showing the codes.

You ask why does the eml keep coming back? The answer is easy as you cannot identify the fault you have not fixed it and the fault remains.

My advice is to get a VCDS scan, the bees knees of diagnostic kit for VAG cars, and you will see the fault codes and be able to set about fixings the fault which is causing the eml.

I am near Oxford, have full VCDS and happy to offer a scan, it only takes 5 minutes, but I am not is exactly local to you. There must be members far more local to you who will help, look in the diagnostic forum, and as a last resort make a general appeal for a local scan. Anybody in DORSET?

Andy
Hi, yes the oil looks good, so it was worth the effort getting the overfill out.
Looks like the cheap scanner doesn't show the data I need, so I actually ordered a proper kit yesterday, thanks for the shout out anyway, and it was recommended by Scotty Kilmer, so should be good.

I got a feeling its gonna be the throttle body, I can't hear any hissing-sound from the engine, so probably isn't intake leak. Although the thr. body was suppose to be sorted by previous owner.
Anyhow the idle 620 is way too low, hence pulling off can be a bit jerky sometimes, so when the scanner arrives I'll give a proper scan, cheers.
 
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I had my EML light on recently, I think my throttle body and EGR valve are both bunged up,

I just went out and gave the car a good blast touching the red line every gear change and the light went off and hasn't come back.

John

Seems like egr and thr. body issues common now days, and I wish most car problems could be sorted by driving fast, but will try that later too :)
 
Take it off and clean it, it's not that hard. I consider it to be a two hour job. Replace the aluminium gasket underneath during the process.

- Bret
 
Take it off and clean it, it's not that hard. I consider it to be a two hour job. Replace the aluminium gasket underneath during the process.

- Bret
As soon as I get the better scanner and see what's the real issue for EML keep popping up, I'll get on the fixing it. Not sure how to do them though, read here you need a vac program to recalibrate the thr. body but probably there's a guide somewhere on the forum, so should be alright. Can't wait to have proper idling and no EML :)
 
Hi,

I think your app is not showing all the fault codes. The light will be on because there is an error stored which is why it goes out when your clear the stored fault memory. The symptoms sound like an additive fuel trim mixture too lean error, something like this:

17559 - Long Term Fuel Trim Additive Air; Bank 1; Range 1
P1151 - 35-00 - System too Lean

A scanner that is able to show everything that's going on will confirm what's going on.

If it is this, then you either have an induction air leak or insufficient fuel flow / poor injector spray.

regards

Andrew

Did new injectors solve it for you? No too lean code coming back?
 
As soon as I get the better scanner and see what's the real issue for EML keep popping up, I'll get on the fixing it. Not sure how to do them though, read here you need a vac program to recalibrate the thr. body but probably there's a guide somewhere on the forum, so should be alright. Can't wait to have proper idling and no EML :)
Not true if the entire readiness code is 11111111; you shouldn't actually need a reader... but having one is a smart move anyway. Cleaning it off rthe car is described in detail (along with details of the tools needed) here: https://a2-freun.de/forum/applications/core/interface/file/attachment.php?id=7995 . You may need to be logged in to download it and it's German but the pictures tell you all you need to know.

- Bret
 
Not true if the entire readiness code is 11111111; you shouldn't actually need a reader... but having one is a smart move anyway. Cleaning it off rthe car is described in detail (along with details of the tools needed) here: https://a2-freun.de/forum/applications/core/interface/file/attachment.php?id=7995 . You may need to be logged in to download it and it's German but the pictures tell you all you need to know.

- Bret
Hi
So I received the proper scanner and the next day the EML came on again, 3rd time right after driving around 60mph for a bit.
Plugged the scanner in and it read the fault code, unlikely the £10 bluetooth one.
The code is "P0401 - Egr A flow insufficient detected".
I'll check the vacuum hoses tomorrow at first. Is the EGR under the throttle body? Can I pull the vacuum hoses simply off, to check for carbon deposits when engine not running or engine should run? I've read it that EGR shouldn't be cleaned as it damages the seals? Thanks
 
Hi,

if you have a 1.4 petrol as per your profile, the EGR is electrically operated and attached to the front of the engine as seen from the front of the car.
The exhaust is directed through the head to the EGR (there is no external pipe on the input) and the output side is the metal pipe you can see coming out of the front which goes across to the throttle.

I have indicated the EGR in this picture:

49157


You are right in staying that the manufacturer's documentation indicates that the valve should not be cleaned. Their opinion is that if its not working properly (i.e. broken) then cleaning it won't fix it. It may as you say also cause it to leak.

The EGR valve does have a calibration operation which allows the ECU to learn the actual closed and open positions of the flap. There is no harm in running this and it may help the valve work better. Note, if you do clean the valve or replace it, you must run the calibration. Especially for replacement, if the valve isn't calibrated, it can damage the valve and burn out the solenoid.

See the guide here.

regards

Andrew
 
Hi,

if you have a 1.4 petrol as per your profile, the EGR is electrically operated and attached to the front of the engine as seen from the front of the car.
The exhaust is directed through the head to the EGR (there is no external pipe on the input) and the output side is the metal pipe you can see coming out of the front which goes across to the throttle.

I have indicated the EGR in this picture:

View attachment 49157

You are right in staying that the manufacturer's documentation indicates that the valve should not be cleaned. Their opinion is that if its not working properly (i.e. broken) then cleaning it won't fix it. It may as you say also cause it to leak.

The EGR valve does have a calibration operation which allows the ECU to learn the actual closed and open positions of the flap. There is no harm in running this and it may help the valve work better. Note, if you do clean the valve or replace it, you must run the calibration. Especially for replacement, if the valve isn't calibrated, it can damage the valve and burn out the solenoid.

See the guide here.

regards

Andrew
Hi, thanks for the infos and the picture. So I can't do this DIY, as need some kind of software to recalibrate to EGR.
Can I remove the output line to check for carbon deposits without needing to recalibrate? Or shall I just ask the garage to have a new EGR installed? Cheers
 
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Hi, thanks for the infos and the picture. So I can't do this DIY, as need some kind of software to recalibrate to EGR.
Can I remove the output line to check for carbon deposits without needing to recalibrate? Or shall I just ask the garage to have a new EGR installed? Cheers
The re-calibration only needs to be done if something physical has changed on the valve. Replacement is one thing as the new valve will be different to the old. Cleaning is another, although if there is some dirt in the existing valve, re-calibrating may correct your problem.

If your new cable has access to the function to run the re-calibration as per the guide above, I would try it. There is no harm and its easy to do, just pressing a few buttons on the laptop.

I would not think your would see much if you removed the output line as the dirt will be on the other side of the valve if there is any, however if you have removed the output pipe, the valve is also off as well as the valve is held by threaded studs sandwiched between the cylinder head on the input side and the flange on the output pipe on the other.

I'm sure replacing the EGR (and recalibrating) would cure it, but try resetting the existing valve in situ first, its quick and easy, and free if you have the function on your new cable.

regards

Andrew
 
The re-calibration only needs to be done if something physical has changed on the valve. Replacement is one thing as the new valve will be different to the old. Cleaning is another, although if there is some dirt in the existing valve, re-calibrating may correct your problem.

If your new cable has access to the function to run the re-calibration as per the guide above, I would try it. There is no harm and its easy to do, just pressing a few buttons on the laptop.

I would not think your would see much if you removed the output line as the dirt will be on the other side of the valve if there is any, however if you have removed the output pipe, the valve is also off as well as the valve is held by threaded studs sandwiched between the cylinder head on the input side and the flange on the output pipe on the other.

I'm sure replacing the EGR (and recalibrating) would cure it, but try resetting the existing valve in situ first, its quick and easy, and free if you have the function on your new cable.

regards

Andrew
Hi, my scanner is this one, so probably can't do the reset, but at least see the fault code unlike the bluetooth one.(https://www.ebay.co.uk/itm/Universa...-Reset-Tool-/292894415194?txnId=1665842594019

I'd get a VAG com cable as well, that'd make 3 scanners in a month :D, see if the reset fixes the EGR , probably still would still be cheaper than doing the same at the garage. Just not sure which one to get, as there's plenty and a 10 quid bluetooth scanner failed on me. Any idea which one is the right one? Cheers
 
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