# Engine turns off while driving



## sheldon0 (Nov 3, 2012)

Hi folks,

for a while now my wife's car has been running fine except for one "minor" issue. Every couple of months and hundreds of miles apart the engine just shuts off while we are driving - Audi a3 2007, 6spd MT 2.0T. It appears to happen while going into neutral (to cruise down a hill or flat road).
Anyhow the first time it happened I blamed my wife's knowledge about using the clutch and that she forgot to press it down while slowing down for a red light. Recently I drove it with 40mph and switched from 4th gear into neutral to cruise down the road - all the sudden I see the Battery light in the dash and think - **** there goes the alternator, however after looking closer it was because the engine RPM was at 0 (shut off) and the key was still in the ON position. So while still rolling I start the car again and switch into a gear - no problems for the rest of the trip.

Bottom line any ideas how to get this fixed or what it could be? I checked with VAGCOM but there are no codes for this.


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## VWAddict (Jun 12, 1999)

*FV-QR*

1) Where are you (country/climate)
2) How old is the battery?


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## sheldon0 (Nov 3, 2012)

1) Location: Colorado/US - it was an average day not very cold and not hot (like 60s)
2) Battery: probably as old as the car ~6years. However we never had trouble starting the car and shouldn't the alternator provide enough juice even if the battery was bad?
-However a new battery is on the list for this year since it has reached EOL


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## VWAddict (Jun 12, 1999)

*FV-QR*

Well, a shorting cell CAN lock up the ECU...

It's VERY rare for the 2.0 engine batteries to last, particularly in warm climates. The 3.2 batteries can run and run, because they're away from the engine bay, but the 2.0T batteries typically last less than 2 years in warm climates, from my experience.

It's POSSIBLE that something crashing the voltage might cause things to cough, but ordinarily there's some physical 'shock' involved like a pothole. -It doesn't sound like you've got any potholes.

It's also possible that your ignition SWITCH (the bit behind the lock where the key goes in, which only turns when the lock is released by having the right key in) could have an intermittent contact. -Does the key 'blade' feel very warm immediately after you remove it after say a 30 minute drive?

Also, the immobilizer could _conceivably_ be acting up. (but I'm not sure if there'd be a vag-com code stored if the immobilizer engages... anyone know?


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## sheldon0 (Nov 3, 2012)

I'll check how the key blade feels after driving for a while and post it here. Also, I do recall seeing an immobilizer alarm in the VAGCom but that was unrelated to the engine shutting off - so far just a random alarm that popped up during regular scanning and not shortly before or after the engine turning off.


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## brungold (Oct 8, 2007)

i experienced a similar issue like this in my 2008 6MT and suggested the dealer change out the ignition switch. no more random shutoffs :thumbup:


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## sivart321 (Mar 12, 2002)

VWAddict said:


> It's also possible that your ignition SWITCH (the bit behind the lock where the key goes in, which only turns when the lock is released by having the right key in) could have an intermittent contact. -Does the key 'blade' feel very warm immediately after you remove it after say a 30 minute drive?
> 
> Also, the immobilizer could _conceivably_ be acting up. (but I'm not sure if there'd be a vag-com code stored if the immobilizer engages... anyone know?


I have/had a similar problem a few weeks ago. My key does feel very warm when I remove it after a short drive. What gives there?

I am still not sure what is causing my issue, but I replaced my keyfob battery and re-paired the key to the car. I have not had the same issue yet, but am not sure if what I did fixed it.

I am curious about the warm key now though. Is that a bad ignition switch?


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## VWAddict (Jun 12, 1999)

*FV-QR*

The battery is only for the remote locking/unlocking/trunk/panic-alarm functions. The immobilizer -as I understand it- uses passive RFID. The immobilizer part of the keys will allow the car to drive even if the battery is dead or not present... Should be an easy test if you're curious.

The current passing through the 'run' contacts is pretty high. any contact resistance dissipates heat. -Next step is to gain access to the switch (removing the plastic cowls etc) and see if the SWITCH is hot. -If it is, it's likely to be ROASTING hot, and if that's the case, I'd probably suggest replacing it.

Mind you, my key gets fairly warm too... -Given that I don't think there's a key-warmer in there, the keysmay just run 'warm'... the question is... HOW warm is "too warm"?


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## sivart321 (Mar 12, 2002)

Thanks for the info. I knew the RFID was passive, but figured it couldn't hurt, and might also help when repairing the key to the car. I was getting an immobilizer code via VAG-Com, but am not sure how much that had to do with it.


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## sheldon0 (Nov 3, 2012)

So, I checked the key after driving to work and the key did not seem abnormally warm or anything. Well I guess I'll just see if the occurrences increase or if I will only have the engine die on me (or my wife) 3 times a year


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## drew138 (Dec 3, 2006)

sheldon0 said:


> So, I checked the key after driving to work and the key did not seem abnormally warm or anything. Well I guess I'll just see if the occurrences increase or if I will only have the engine die on me (or my wife) 3 times a year


*DEBBIE DOWNER ALERT*

Dude, take your car to the dealer or authorized audi service center immediately. Please don't take risks with your wife's life as this is a pretty serious condition that could cause serious harm to your family or others on the road if this issue decides to rear its head an in inopportune time. This isn't like a random bulb out warning, this is your entire ENGINE shutting down without warning.

Good luck. Sorry for the lecture. Peace! :thumbup:


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## JDBVR6 (Dec 29, 2006)

drew138 said:


> *DEBBIE DOWNER ALERT*
> 
> Dude, take your car to the dealer or authorized audi service center immediately. Please don't take risks with your wife's life as this is a pretty serious condition that could cause serious harm to your family or others on the road if this issue decides to rear its head an in inopportune time. This isn't like a random bulb out warning, this is your entire ENGINE shutting down without warning.
> 
> Good luck. Sorry for the lecture. Peace! :thumbup:




I concur 100%. Just bite the bullet.


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