Car won't stop!

6) It’s possessed by demons and will need to be exorcised by a German priest….

Go on then, what happened, what happened?

7) car has had a johnny 5 like moment and after its owner posting a what shoes tread on STW decided it could no longer rely on it’s owners own decision making skills and has finally taken control of it’s self !?!? 😉

Hope you have managed to get it sorted mol, sounds a very weird fault.

Still buggered after leaving overnight. Booked it in with a mobile mechanic, and he mentioned it might be some wires having shorted out confusing the ECU. I saw similar when googling.

It’s very unethical to use this tip to try and fix it myself, but I’m that strapped for cash I might have to.

Check the footwells for damp. This is usually the cause of electrical gremlins on VAG cars due to the number of computers that live in the part of the car most prone to flooding.

However, I’ve never heard of it causing your particular problem before but when the alarm wouldn’t stop going off on mine this was the cause.

^^ This. Maybe it’s sorted now but in my 2001 Passat the drain holes under the battery got blocked so that water started coming in via the hot air ducts. Fortunately it didn’t get into the ECU before I sorted it but that used to be a standard way of borking the ECU at which point all sorts of weird alarm and electric window behaviour would ensue.

hamishthecat – Sounds similar to my brother in law’s Audi A4. 2 drain holes under the battery blocked. Every time he went round a roundabout all this water sprayed out the side of the bonnet.

Others have beat me to it one of the main electrical control units sits under the front passenger side carpet and when it fills up with water it causes horrendous issues. I know as my 1998 Passat estate had a cracked pollen filter housing (from when it had a new screen fitted) but took a total strip out of dash etc etc to see where water was pouring in!
Had to have it all dried out and some patches on the circuitry re soldered etc. It is also very common for the drains for the air con to get blocked and dump water into the front nearside as well as the bulkhead under the battery drain holes to get blocked particularly if you are a biker parking in the forest- pine needles are a bitch!
One other thing that will cause a diesel to run on is if the small end plug on the return fuel flow through the injector pipes has popped off or split. When it pops off you do spray gallons of diesel but a small hole will cause the issue.

Maybe it’s sorted now but in my 2001 Passat the drain holes under the battery got blocked so that water started coming in via the hot air ducts.

Must be changed now. I just had the battery and airbox out to follow the ECU wiring as far as I could, checking for breaks. Underneath the battery is a load of wires and space, so it’s different to what you’re saying.

No evidence of damp in the car at any rate.

The ECU is under a panel at the foot of the windscreen, where the windscreen wipers go. It seemed to be pretty dry but at either end of that channel the drain areas were blocked with actual compost formed from leaves and pine needles. Got rid of all that, but no change.

It’s not simply running on, btw – the ignition is permanently on. All interior stuff still on when I remove the key, trip computer the lot.

I had the same damp issue in an 05 passat. Damp passenger foot well, under the carpet – you couldn’t feel it from the top. Borked some wiring and a crash sensor. Never got to the bottom of where the water was coming from – it was time for a change anyway, so I just punted it.

Will go and check the carpet then.

Sounds like a fried wiring loom. A Rover 400 I had did some strange things before filling the car with choking smoke. I had the dash out & all sorts but it was just too far gone.

I wasn’t too saddened by its departure on a flat-bed truck.

We have a Galaxy, (same as a Sharran), & they have known issues from a flooded area under the passenger seat.

So hang on. If your car’s ECU fails, you get a huge repair bill. If it fails really badly and catches fire, destroying the car, you get to claim on the insurance?

Hmmm….

Aaahhh, fraud. Top idea! 🙂

rather than water in the electrics it could be fuel. Some diesels have issues with tiny fuel leaks inside the pump, fuel gets drawn along the inside of wiring like a wick, inside the insulation. Depending how the loom is configured it can then find its way into the ECU.

Just replaced the ECU on my vauxhall for exactly that reason. Luckily its such a common fault on those cars you can pick up re-coded, remanufactured ECUs for (comparative) peanuts. Solving the contamination issue is done by cutting the fuel pump wires and re-connecting them with choc-blocks so that you stop the wicking effect.

Contact an ECU/tuning place, sometimes you can provide a second hand ECU and they can make a copy of your bust ECU.

Update:

Man came to read the codes and it reported all sorts of disastrous and random stuff. Conclusion, ECU is indeed borked. Removed the unit, it showed signs of having been immersed in dirty salty water half way up it, which is bizarre because whilst there was water pooled in the trough where it goes cos the drainage was blocked with leaves, the water level was nothing like high enough. If it had got that high it’d have gushed into the cabin since the cabin air intake was about 6″ lower than the ECU.

It was continuing to be fairly random and show differing symptoms though, so there’s a chance there’s water actually in it and moving around.

It’s gone to a specialist place in Pontypridd.

It’s gone to a specialist place in Pontypridd.

Eh?

Tssssk Moly. That’s Daffyd, the only gay in the (Llanddewi Brefi) village. 🙂

Anyhoo, have you bailed out yer Passat yet?

Not sure if I am too late, but some knowledgable folk on UKpassats.co.uk forums might help.

Tssssk Moly. That’s Daffyd, the only gay in the (Llanddewi Brefi) village

Yes I know, but what’s that got to do with me sending my ECU to Pontypridd? Unless you’re associating everywhere in Wales with that one particular sketch for some reason. Which would be a little odd!

Popstar – Googled a lot, including on that site – hardly anyone had these problems.

Update:

ECU case was so badly corroded it let in water. Wtf? Impossible to imagine so much water in that area under the windscreen that it would have been sitting in water.. maybe continual exposure to water and salt etc.

Anyway, they are charging £550 +vat for a recon ECU. Does that sound decent? Is there likely to be any way to get it cheaper?

£300 on ebay if its the same part

There are some for £100.

I just think it could be a world of pain trying to plug in a new one….

For that ^^ kind of dosh I’d expect a new ECU WITH warranty.

Once had an ECU fail on my 3.0Ltr Peugeot. Very expensive.
Last French car I’ll ever own.

The area beneath the windshield can easily flood, on a lot of cars. Most now have drain features to direct the water out, but…. the drains get clogged with leaves, dead bugs, twigs, etc.
FOr future ref, it may be worth finding the drains in the cowl / scuttle area and checking / clearing them just occasionally.
Also not parking under trees, etc, can help prevent debris falling onto the windshield and down into this area.

Still, imo, OEMs should make a better job of protecting such crucial and expensive components, from this type of damage.

Have a sneaky feeling that it’s the kit to reset / get the car actually working again that you’re really paying for there. Sodding expensive! Just a thought, there are a few ‘chipping’ companies that have all the plug in gizmos, maybe they also can set up a ‘normal’ one? A friend at work has just had his 08 Passatt CC chipped for £240. (yes, I know it’s all programs on the chipping front. however you get my drift)

For that ^^ kind of dosh I’d expect a new ECU WITH warranty.

Well this one does come with 12 months warranty. VW wanted a grand apparently.

The place where it sits had blocked drain areas, but the ECU was higher up than the air intake for the car, so water would have drained into the car before submerging the ECU.

Let’s say £300 for recoding, and £200 for the new unit – then add VAT and the initial diagnostic time – not that different.

Cheap!

You can’t just buy a second hand ECU and fit it. It needs to be programmed to the car. This sort of equipment is not cheap to buy and has to be constantly updated with paid for updates. One of my tools costs over £700 p.a. to update and that’s a cheap one.
Hth
Marko

Well this one does come with 12 months warranty. VW wanted a grand apparently.

Peugeot wanted over £700, and this was quite some time ago now. I pointed out that they needed to help me with that as the car was low mileage, FSH and that they couldn’t prove it wasn’t a flaw. Just ask for a little understanding and try getting different dealers to quote.

I had to replace a turbo on a VAG car once. One dealer wanted the work more than the other, it would seem and I got 50% off.

The place where it sits had blocked drain areas, but the ECU was higher up than the air intake for the car, so water would have drained into the car before submerging the ECU
Well thats a design fault then. VW can’t tell me that with all their testing that this fault had never occured during testing. Corroded boxes containing the ECU ?, in nowday ?. Not acceptable.

Apparently the one that’s failed is the main one, and most of the coding is the subsidiary ones. However, I’ve gone with the professional route anyway.

Well thats a design fault then

Well.. let me explain. Under the windscreen on most cars is a trough in which sits the windscreen wiper gubbins, the air intake and a few bits and pieces and on my Passat, the ECU. The trough is curved down at the edges so water runs down either side and down a gap (not really a hole) into the wheel arch. The air intake is protected by about a 3″ high bit of plastic all around it. The ECU sits probably 3″ above the floor of the trough and due to the curve about 6″ above the drain hole. So it cannot sit in water.

It looked like it had been sitting in water, but it must’ve been continual spray from the wipers, or road spray. No idea why tbh, everything else in there looks ok. I may try covering it up with something further, plastic bag, zipties and some scilica gel maybe, dunno. Or just try and keep it clean regularly.

The drain gaps to either side were blocked with a lot of pine needles and leaves. There probably should be a baffle on the air intake holes on the outside of the car to stop that happening, for sure.

Mol, when are you going to give up on that unreliable, expensive German shitheap an get something decent?

Every time you mention it on here you’re chucking more and more money away on it. Give up man. Really.

Double post

What’ve I spent on it lately?

According to two different mechanics I’ve spoken to, they are very reliable. I understand that a sample size of 1 is not representative, so I am so far content.

How much money should I spend on a new car, and how much will I be guaranteed to save?

Oh and whilst we are at it, when are you going to stop telling me what to do and insisting everyone else does the same as you?

And can I tell you to get rid of your crappy car if it breaks down?

Cheap!

no £200 (inc postage) for a remanufactured ecu, with warrantee, coded from your old one, is cheap. But for that you need to drive a model of car where ECU failures are so common that a cottage industry has grown to meet the demand for replacements.

How much money should I spend on a new car

as much as you like – you say yourself that the capital purchase isn’t considered part of the running costs of the car. LOLz 🙂

Initial purchase isn’t part of running costs, of course.

I was taking the mickey out of PPs idea that I should spend money to save money, when there’s no guarantee that any will in fact be saved.

I had the ECU on my car go after a windscreen replacement wasn’t sealed properly and rain got in. Took a good 6 months for the issues to manifest, but full credit to Autoglass, they put their hand up and covered my repairs.

Doesn’t help you though, soz.

Was the ECU inside the car? I had a new windscreen when I got the car in 2009, but I can’t see how that affected it. Unless it was the disturbing of the cover, but really I don’t think it’s designed to be waterproof anyway.

Molgrips, just seen this and not sure if the same but had a very similar problem on my Audi a6. I know that Audi vw share a lot of parts so whilst this might be completely irrelevant it may help.

I had exactly the same problem with water getting in from somewhere around the windscreen and in the end we discovered that there was a hairline crack in the pollen filter which was leading to water getting everywhere. It screwed the electrics up no end.

If the passat has a pollen filter around that area check it carefully, apparently they break easily and can cause problems.

Thanks

Luffy

Thanks. Was your water getting inside the car though? This particular ECU was outside the cabin and in the segregated area under the bonnet.