Hi all,

 

Last night my Octy VRS TSI cut out very suddenly on a motorway roundabout with a sudden loss of power.  Seemed like it had just lost electrical chrage, and most (if not all) of the warning lights lit up on the dash.  It then wouldn't start, and started showing all the weirdness on the electrics you get with low battery voltage.

 

Called the RAC, but they weren't able to work out what the problem was, and worryingly their OBD reader wasn't able to get any sense.  After giving the battery some charge, they managed to get the engine started for about 5 seconds before the EPC and engine warning lights came on and cut the engine.  About 10 min after having the battery topped up from an external charge, there wasn't enough juice to turn the hazards on.  They gave up and suggested I got it towed.

 

I'm worried that somehow my ECU has fried somehow - and if it is that, a replacement is going to be £1700 (and will take weeks to sort).  It has been very wet recently, and I did get it washed a couple of days ago, but I can't see any real reason for the ECU to have got damp.

 

As I've got an STS box from Shark, I used that to try and read the fault codes, but it gave up after 'trying to connect with the ECU'.

 

Going to get a mobile electrics guy to look at it, but can't find anyone who will come until Monday.

 

Is there any hope?

It sounds like battery failure. Remove the battery and get it tested.

I agree with the above. Just get the battery off and tested. Sounds flat to me. Did the RAC check all the connections on the battery and alternator?

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New decent battery will be first port of call. We've had cold weather again lately and that will finish off a weak battery!!

double post sorry

Edited 3 March, 201610 yr by Vegasphil

Varta 096 silver dynamic will be best choice

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Do cars not run on the alternator once started though?

Do cars not run on the alternator once started though?

 

Alternator is the main source of electricity while running.

Alternator is the main source of electricity while running.

 

Precisely, so if the car is just dying mid drive, would that not suggest alternator, rather than battery?  If the battery is fully charged, it would start the car and drive for a bit then conk out, and with a knackered alternator, the battery wouldn't get charged. I think?

The fault may be in both.  If the alternator hasn't been working properly, the battery will die from lack of charging; and there won't be enough juice from a faulty alternator to run the car without the battery.

The fault may be in both.  If the alternator hasn't been working properly, the battery will die from lack of charging; and there won't be enough juice from a faulty alternator to run the car without the battery.

Yeah that's what I was thinking.  Take even a deep cycle 12V Pb battery lower than 10v and it'll be shot.

If you know someone local who loan you their battery to test your car then get it fitted and test the output of the alternator at the battery with the engine running. If it's not putting out more than 12v then you'll need to replace the alternator. Battery may be recoverable with long charge but if not get that replaced too. Won't be cheap but a lot less than an ECU.

I wouldn't take it to a main dealer who will just replace parts until they get it right but instead see an auto electrician. 

If you know someone local who loan you their battery to test your car then get it fitted and test the output of the alternator at the battery with the engine running. If it's not putting out more than 12v then you'll need to replace the alternator. Battery may be recoverable with long charge but if not get that replaced too. Won't be cheap but a lot less than an ECU.

I wouldn't take it to a main dealer who will just replace parts until they get it right but instead see an auto electrician. 

 

^ This is what I'd do.  You should be seeing just over 14v when the engine is running and the battery charged if the alternator is good.  If the alternator is good, then it's likely a dead battery. Much cheaper than an ECU

Gentlemen, you are entirely correct - just whacked a new battery in, and everything appears fine 

 

Wouldn't want that to happen again though - it could be pretty dangerous if it happened in the wrong place. Do you think I should get my alternator checked out, or do you reckon it was just a shot battery?

Do you think I should get my alternator checked out, or do you reckon it was just a shot battery?

 

Wise to check. Get a voltmeter (multimeter set to 20 or 200v DC range). Check for voltage between 14.0 and 14.6 volts across terminals with engine running and headlights on.

 

Surprised that RAC couldn't diagnose such a basic fault, you need to complain.

Edited 4 March, 201610 yr by xman

Thanks for that - I'll check it out.

 

Agreed about the RAC - I don't think they are the organisation they once were...

 

Agreed about the RAC - I don't think they are the organisation they once were...

 

Agreed on RAC, spent half an hour on my wife's Mercedes swearing that it was flooded before I got it through to him that I thought maybe the lift pump wasn't working? Tried to run the lift pump with manufacturer software and it wouldn't run sooooo, he blamed the software? and towed the car in. Turns out it was the fuel pump relay.

The plot thickens slightly - I just went outside and noticed the radiator fans were on, even though I hadn't driven for about 30mins  From a read on here, seems like this is a classic symptom of moisture in the fuse box.

 

When it stops raining I'm going to get a hairdryer in there to remove any residual moisture.

 

I'm not feeling quite as critical of the RAC man now.

Are you sure it's not a DPF regen. 

 

Get the alternator checked before you knacker another battery.

Yeah, definitely not DPF because it's a petrol.

The OP's opening post said TSI

Forgot that detail just mine does that if it's entered DPF regen mode. Having the AC on can keep the fan running too but that's normally in hot weather.

Just checked out the alternator - seems fine, but there is a bit of moisture around the fusebox.  My theory is that moisture got into the fusebox, causing a problem that made the battery drain quicker than the alternator could replenish it.  The fusebox lid may not have been on properly (although can't tell for certain because the RAC had already removed it).

 

Anyway, seems to be sorted now so thanks all 

Edited 5 March, 201610 yr by cupachump

Arrggh.

 

It cut out again this evening, and is now stranded miles from my house.  It is exhibiting the identical symptoms from the following thread (e.g. fans running up randomly, clicking from the relay, engine only starting sporadically but cutting out after a few seconds).

 

http://www.briskoda.net/forums/topic/270207-disaster-a-fried-ecu/

 

I now think that my initial hunch was correct, and there's something physically wrong with the ECU board.  I'm hoping that it's simply a bad solder connection because it seems to be intermittent.  I'll try and get hold of a mobile electrician who can get the board out and have a look.

 

Morning Chupachump

 

I know how you feel ....

 

http://www.briskoda.net/forums/topic/390315-06-l-k-ecu-problems/

 

Good luck with it.

 

Cheers

 

Dave