What a bonkers 24 hours this has been for my poor Passat B6 2.0 TDI auto.
Last night, drove home no issues. I couldn't sleep as it happened, so came downstairs to watch telly, the alarm's going off. Odd no break-ins, car is locked. Unlocked and locked it, still kept going, then it stopped on its own later.
Came to drive today, totally dead, . So I removed the battery and the alarm went off! Wtf, there must be a spare battery somewhere to power an alarm when the battery's disconnected. Well that explains last night - something was draining the battery and it went low, alarm went off.
Charged the battery just now, drove to Tesco. It was a bit confused as usual after a flat battery - ESP, power steering lights on, cruise control doens't work - this usually sorts itself. All lights off by the time I got to Tesco, no worries.
On returning to the car, I see that the BRAKE lights are on (not tail lights) despite me having locked it. Weird. Well on the way back a few other lights are on that weren't on on the way over. Not so good. I get home, turn off the car, the engine doesn't stop! Remove the key (it's one of these push-fob things), still running, get out lock the doors - still going. So I disconnected the battery, the aircon etc stop but the engine is still going! It's still going now, I'm waiting for the breakdown man!
WTF? Seriously!
stall it
Automatic.
Exorcism?
Its probably pretty hard to stall an automatic
Drive it into a canal
stall it
Not easy to stall an Auto box!
Running on its own sump oil? 😉
More than likely though, you've got some serious electrical gremlins manifested themselves, and you need to get it connected to a VAGCOM asap and get the fault diagnosed and fixed.
Wierd. Why can't you just put it in gear and stall it BTW?
Too slow 😀
Low battery power can do weird things to the ECU as the car tries to 'power manage' what there is.
I once had a car which wouldn't switch off - I was driving down an A road and the turbo had started to use the oil sump as fuel (or something like that). Anyway, there was loads of smoke and the car behind me phoned the fire brigade and I got a lift in a fire engine. It was quite exciting.
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More than likely though, you've got some serious electrical gremlins manifested themselves
Really? 🙂
Any ideas on how to stop it? I'd unplug the ECU but that doesn't seem to be particularly easy. I considered clamping the fuel line but I really don't want to wreck any expensive high pressure fuel pumps by starving them (or overloading them if I clamp the return instead of the inlet).
Block the air intake with something that can't get sucked in, rubber floor mat or something. You can also use a C02 fire extinguisher if you are desperate, but don't freeze your hands to the nozzle 🙂
Sounds battery/alternator/earth strap related.
Not easy to stall an Auto box!
I once owned a Fiat Panda auto (don't ask) that stalled roughly once every couple of drives. Bloody awful car, that was.
Personally I'd be calling up the local priest to carry out an exorcism.
get some thick plastic and cover your hand then block the exhaust
I did consider blocking the air intake. Dunno how much suction would be generated as it opens the throttle to keep the revs up.. could be nasty.
On my old car I put my hand over the inlet and it really sucks like hell. Definitely not doing it with my hand.
Better to stop the air and suffocate the engine than try and strangle it by blocking the exhaust!
If it throttles up it will need more air. Just don't use a plastic bag as it could ingest it through the turbo.
P.S Too late now but you should never disconnect the battery with the engine running, it can kill your alternator.
If it throttles up it will need more air.
Yes and thence suck harder, possibly causing some damage or other. Disconnecting the ECU would be best I reckon.
Cellotape some cushions to the front and drive it very slowly into a wall.
i would hope the air filter would block a plastic bag!
Did you drive back in the rain? Check for some connectors that can easily get wet around the front or wheel arches as it sounds like the ignition circuits are getting kept live. To stop it you could undo the battery as a modern diesel needs electronics and then turn on every electrical item (lights, stereo, rear heater etc) and press all the electric window buttons up when closed to try and use all the electricity the alternator can supply.
My car has a fuel cut-off (under the passenger seat IIRC) does your manual mention anything?
No, no rain.
There was a slightly odd smell in the car, a little bit like burnt electronics... I at first thought that the 5v power supply I'd bought off ebay a few weeks ago to power a USB HD had burned out somehow and drained the battery. Reinstalled the original radio before I went to tesco just to be absolutely sure about the current drain. I've suspected the aftermarket stereo before.
Will check!
😀Cellotape some cushions to the front and drive it very slowly into a wall.
Taking the battery out is a bad idea esp as the alternator will keep it going even with everythjng on - the revs will just climb a bit to counter the load
If you decide to unplug the ECU I'd be leaving that to the AA man. Could cause all sort of issues, sensitive electrickery and stuff. Might not even make any difference, its probably the stop solenoid stuck open which would normally close when you turn off the key/the battery goes flat.
I don't think blocking the intake can cause any damage, it will just lose power and refuse to rev, if you get a good enough seal it will stop. The suction is only created by the combustion.
The alternator will be able to supply around 90amps...you'll never consume that much power (except for the starter). I didn't think about the alternator supplying the stop solenoid. I suppose you could disconnect the alternator earth strap but probably hard to find in the dark, plus it could kill the alternator if its not already dead.
Can you block the air intake? Don't know if that is a good idea or not.
Taking the battery out is a bad idea esp as the alternator will keep it going even with everythjng on - the revs will just climb a bit to counter the load
just block the exaust, it work or it did on my dads morris ital I'm sure nothing has moved on much since then
What about a co2 fire extinguisher at te air intake ?
Burn it ....
How about you jack it up, get it into drive and up to speed and then knock it off the stands. If it is a robotised clutch rather than a traditional auto I bet that will stall it. Remember to leave the cushions in front of the car 🙂
I struggle with long sentences
Disconnect the fuel supply
Actually thinking about it, I think the fuel cut-off switch in my car just re-enables fuel once it's been cut off when the engine detects a problem. It doesn't allow me to disable it.
Ignition switch issue? Pull fuel pump relay or power supply relay out of fuse box, not sure of relay numbers from top of my head. That model Passat suffers from immobiliser issues (inbuilt into convenience ECU behind the glove box) and also electric steering column lock ECU issues.
Open the water drain on the bottom of the fuel filter & it will draw in air & stall.
Disconnect the fuel supply
Very very messy. The pump would continue to run for a fair while. Bear in mind the engine's really hot at this point and hard to work on!
Green Flag man removed the big relay from the fuse box - job done. Brake lights permanently on now though - battery is now disconnected.
The possibilities:
1) It'll reset itself overnight off the battery
2) It can be reset with VAGCOM at the garage
3) It can be completely reprogrammed (Green Flag man suggested a normal performance remap..?) and will work
4) The wiring loom's damaged and confusing the ECU
5) The ECU's totally borked.
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.
