Guide: ESP Light On- Glow-Plug/Engine Light Flashing - Cause & Fix Inside!

[Yoof]

Afternoon All,

Driving in my 1.9TDi A4 yesterday through lots of rain, I got off the M1 and the esp light came on, and the glow-plug light started flashing, leaving me in limp mode (1100rpm and no throttle) and a max speed of ~40mph.

Whilst waiting for the AA man I sat with the heaters on my feet, and the problem stopped...

So, here's a quick guide to save you from going through what I did!

Problem:

ESP Light on, Glow-Plug Light Flashing, Loss of power, In limp mode, 1100rpm- usually happens in wet weather, or just after washing the car. Carpets being damp in the footwell are an early warning sign- heed the warning!

In some circumstances you may find the rear brake lights don't work (mine still did).

Reason:

Drainage holes blocked, or ECU housing seal refitted incorrectly. Eventually this allows water into the cabin and meets the 4 vehicle interconnects, OBD, brake/throttle pot.

Once the circuit shorts on the brake/throttle pedals, the EMS gets the hump, there's a rationality check done between the rising and falling potentiometers on both pedals, if these don't correspond, the EMS will put the engine into limp home mode.

The AA diagnostics didn't show anything- I believe VAG-COM/Diagra etc will show a brake pedal switch fault.

Solution:

If this happens to you on the move- put the heated footwell on full and wait for an hour or so. Beware the reason this is happeneing is water has shorted electronics, removing the ESP fuse won't get you out of limp-home mode either, so proceed with caution.

Tools required:
Torx Sockets/Keys
General Toolkit (Sockets: 10mm,16mm) Various Spanners, 6mm Allen key
Silicone Sealer
White Spirit/Petrol
Petroleum Jelly (Or Grease)
Toothbrush
Torch/Light
Rags

1) Remove the scuttle tray cover and remove the battery (10mm Spanner & 6mm Allen Key)

2) If not already done, remove both drainage holes and clean/enlarge or remove completely:

Under the battery:



Under the brake servo:



3) Clean around both holes and remove and leaf matter from the scuttle area. Follow the next steps if you still have a problem with water in the cabin.

4) Remove the driver's side wiper (16mm Socket):



5) Then use a T30 Torx bit on the 5 securing screws- mine only had 4 on, it was obviously too much of a pain for Audi to do the job properly in the first place...

6) with the top half of the ECU housing removed inspect the seal:



It's probably past it's best, I'm waiting until the New Year and I'll order one from Audi- will post up Part # & Cost when I do.

7) Unclip the ECU and remove the right hand connector- this should be placed ontop of the engine out of harms way.

8) The lower half of the ECU housing is where the problem lies, there's a rubber seal between the body and the plastic housing, if this has perished, or been refitted incorrectly, it will let water in. Remove the housing using a 10mm socket and an 8mm one for the front nut.

9) Use a 10mm socket for the nut securing a positive feed (the nut is captive so it won't drop)

10) Unplug 4 interconnects; White, Black, Red and Beige (these can only be fitted in one direction so don't worry too much about remembering)

11) Lift the lower housing clean of the scuttle:



12) Left this- you can see the water/leaf mess which was causing problems:



13) Inspect the rubber seal, and replace if necessary, or clean and reuse. To avoid the seal dropping out whilst refitting I used a small bead of gasket sealant to hold it in place:



14) Clean the mating face on the body:



15) Refit the seal:



16) I then used some vasilene on the mating face for extra security- I didn't want this happeneing again:



17) Refit in the reverse of removal, making sure the seal is located properly, otherwise this is all in vain.

18) Refit battery and re-code stereo/drive to get the ESP light to go off.

19) Dry out footwell and inspect connections on pedals for corrosion/water damage.


All in this took about 2.5hrs, I left a fan heater drying the footwell carpet out whilst I was working. Hopefully this helps people with a common Audi problem, if you know your car has had a replacement wiper motor, or any work done in that area, I'd inspect the seal- it's never nice to be stuck with a car in the hardshoulder on December 23rd...

Cheers

Pete

[quattrojames]

Nice write up, thank you.

I think your reference to the brake lights not working is because sometimes the ESp and glow plug lights will come on when the pedal switch has failed.

[kite]

I had this seal fail last year, it was just after having a new screen fitted
I thought the problem was a badly fitted screen but by removing the drivers side lower dash andlooking up
with a torch I could see the water dripping in when a mate was playing a hosepipe over the front.

Great write up

[audigeezA4]

great advice and very useful, unfortunately a bit late for me as this was exactly the issue i experienced last week also.....however i was unlucky that i had a to go through a breakdown to resolve, but lucky for me, as audi had failed to fix this same fault in the past, this time it cost me nothing but inconvenience to rectify. oh and they did fit a new ecu last time but only replaced the housing cover and not the bottom part apparently which was leaking!

[Yoof]

Glad it's helped- a poor design on Audis part doesn't help matters, nor does the general crap drainage design of the B5-B6 Audi and Passat era vehicles. Minimal monsoon testing I think...

My drivers side carpet has a small damp patch after the last two days of rain, unsure if it's still drying out or fresh water coming in at the moment...

[qro-qrm]

Call me stupid and flame me if you like but... I am looking at the pictures trying to see these things I need to remove but I am non the wiser.
My B6 just came up with this symptom after a drive today in the foul weather.

[quattrojames]

Its the weatherproof box the ECU sits in. It's located on the offside (drivers side) adjacent to the wiper spindle.

It might be under the scuttle cover if one's fitted (athough it is cut out around that).

[qro-qrm]

Thanks quattrojames,
The bit I am struggling to see in the pictures is the drainage holes, having to remove from them I assume there is a drainage grommet or the like, Having not got a clear view of mine in the dark I am assuming on the pictures something is already removed from the holes but which holes are they?

[quattrojames]

If you look in the DIY Guide's sticky at the top of this section you'll find a link to removing the Plenum Chamber Gromets - that should answer all your questions hopefully.

[audigeezA4]

i am sure someone will correct me but i believe one of the grommet holes is located under the power steering servo(round cylindrical thingy), well, thats the one i pushed through to let water out anyway. i am sure there is a thread ref: plenum chamber which shows location of exact holes. As for the weather proof housing for the ecu that sits directly under an area which will experience high water contact, i agree, not the best of designs or that logical, but hey, what do i know....any damp patches in the drivers footwell carpet, then i would be extemely concerned and get it looked at before its too late.

[audigeezA4]

If you look in the DIY Guide's sticky at the top of this section you'll find a link to removing the Plenum Chamber Gromets - that should answer all your questions hopefully.

too slow with my response, as usual, must be the old age, i better wish everyone happy new year now!!!! before i'm late with that as well! lol

[quattrojames]

too slow with my response, as usual, must be the old age, i better wish everyone happy new year now!!!! before i'm late with that as well! lol

Lol, you wrote your response though, I cheated and didn't even give the link, just the location of it!

Happy New Year

[audigeezA4]

Lol, you wrote your response though, I cheated and didn't even give the link, just the location of it!

Happy New Year

lol.... happy new year!!!

[qro-qrm]

well I have drained the chamber, my guess about 5-10l of water came out.
Still got the two lights on the dash.
Sat with the car running to get it hot (max temp) taken for a short drive in limp home mode.
Now leaving it till after the new year to see if its going to dry out and sort itself out.

Only thing I just realised I haven't done is check the pedal switch connections, will do that and if still no joy will be taking to my local specialist to have a look for me.

[qro-qrm]

A new point to post on this.
I now do not think its anything to do with water ingress so this might now be the wrong place for this post but here goes why...

With the car sat on the drive and the engine NOT running, I turn the ignition switch to the second click, just prior to start up.
If I just depress the accelerator the lights come on and pre-heat flashes.

I am guessing that the ESP and flashing pre-heat hide a myriad of possible issues.

I am also assuming here I must have a diagnostic tool connected to see the error codes.

I am now guessing that it may be the accelerator switch.
Would the diagnostics show this???
Jumping the gun a little but what sort of damage would I be looking at for a new accelerator assembly?

[marktdisport]

could the fault be the headlight switch be faulty ????

[qro-qrm]

could the fault be the headlight switch be faulty ????

All lights work perfectly.

[duffer]

I think, I too have been victim to this problem........

Driving home on New Year's eve on a very busy M4 in heavy rain with wife and 9 month old twins onboard!!!

Symptoms much the same as many those above:

ESP light, Coil Light (constant not flashing), 1100 rpm and no throttle response.
Had to pull onto hard-shoulder just before all getting out to stand in the rain and await rescue I tried a restart. Bingo - no warning lights and we drove home another 100ish miles.


Assuming you guys think this is the same problem I plan to:
Remove the battery and clean the drain holes thoroughly.
The car is due a service at my friendly local garage so I will ask them to put the car on the VAG diagnostic machine and change the seal on the weatherproof (ha ha) box and inspect for any signs of damp. Did anyone have a part number for the seal?

Does this all seem sense? I really don't want this to happen again it was not much fun - in fact, dangerous.

Thanks for all your time and advice - information like this help to break the dealerships bankrupting us all !

Duffer

[qro-qrm]

Well I now have the answer/solution thanks to Pete from Towcester VAG.

The diagnostics showed an throttle error saying the signal was unintelligible.

He has fitted a new accelerator assembly for me this afternoon and its all OK again.
Nice simple job which TBH I could of done myself but now I have made a nice new acquaintance with a very friendly and helpful local mobile mechanic with superb Audi skills and background.

I hope he doesn't mind me saying but if you have an issue or are looking for someone who in my opinion is 100% in the South Northants area he is an excellent choice, he is listed on this forum which is how I found him.
Send him a message as I did via View Profile: towcestervag - Audi-Sport.net

[miniredcooper]

Great write up.

Does anyone have the part number for replacement seal to hand (before I trawl etka!).

I have a swimming pool in floorwell which I cleared a few weeks ago -cleaned plenum plugs (and boy were they gunky!). However problem returned. Thanks to quattrojames, ended up here and lo and behold the seal was poorly fitted and actualyy has a couple of cuts to it. Hopefully this is now my problem solved (after a new seal of course!)

[kite]

Don't think the seal is available on its own. I had to buy a new box.