Golf mk6 tsi - battery went flat, now won't start

[rickyquicky]

Hi guys

Any advice would be much appreciated. Golf mk6 1.4 Tsi DSG

My girlfriend was waiting to pick up a friend and sat in the car, engine off, radio on (she didn't say but probably lights too). Prize in the post to who can guess what happened 20 minutes later....!

It turns out someone stopped and connected up some leads to try and jump start it with no luck. AA man then came out, connected power pack, still wouldn't start, so plugged in his computer and said no fault codes. He said fuel was there but other than that could only guess that the car has gone into safe mode.

Car got recovered home and now we need to sort it, does anyone know what could have happened? Have heard it could be a safe mode, could be a fried ecu.

Any things I can do/check? Anyone with vcds around bexleyheath, Kent?

Cheers
Ricky

[bigjobbo]

I have never come across any vehicle in 'safe mode' . Is the engine turning over? Has the battery been recharged?

[rickyquicky]

Hi, thanks for the reply.

So now you put the key in and everything lights up as normal, then engine will turn over but will just not 'fire', it will just keep turning over without actually starting.

At first when we put power to the car again the electric windows didn't work, but now do if that means anything

Cheers

[bigjobbo]

I would first check fuel, spark and compression to eradicate the possibility. I have to ask, is it possible the battery was drained from trying to start the vehicle, and not the radio?

[YankeePorker]

Without knowing these cars at all, one thing I'd try before going further in the diagnostics is disconnecting the battery leads for a few minutes, then reconnect and let the car sit for half an hour before trying to start it up. Maybe it would be to no avail, but a vague attempt to reboot the car's brain!

Another potential point, does it have an immobiliser system that needs resetting? Just googled it, and it seems owners have had none starting issues related ton the steering wheel lock sensor. Try turning the wheel to engage the lock before trying to start it?

Edited by YankeePorker on Saturday 18th October 16:51

[rickyquicky]

Thanks for the replies so far.

Little update...

Got my hands on a snap-on ethos scanner, it came up with 24 various fault codes, but nothing from engine control module. When trying to connect, it would just come up with an error that it could not identify engine control module.

Sounds like the ecu is buggered then?

Is there a fuse for the engine control module?

Cheers

[SMB]

rickyquicky said:

Thanks for the replies so far.

Little update...

Got my hands on a snap-on ethos scanner, it came up with 24 various fault codes, but nothing from engine control module. When trying to connect, it would just come up with an error that it could not identify engine control module.

Sounds like the ecu is buggered then?

Is there a fuse for the engine control module?

Cheers

If it had 24 fault codes it was talking to the ecu, was the fault code reader can bus compatible as that may explain the identity issue.?
What were the fault codes? Being in mind many may have been caused by the flat battery

[rickyquicky]

The 24 various error codes were for each different system, so there was a few for air-con, a few related to power steering, electric windows etc...all were along the lines of insufficient voltage so that made sense, so all related to flat battery obviously.

Im not sure if it's canbus compatible, its a snap-on ethos+ scanner if that means anything to you.

I could then go into each 'menu' for the various systems in the car so I could clear them (steering/transmission/etc) but when I attempted to go into the 'engine control module' menu it would just say "unable to connect is cable connected and ignition on?" because it wouldn't communicate with engine control module obviously I couldn't then access the menu to read any codes.

That led me to believe it's a problem with the engine control module?

Is there a fuse or relay for the engine control module?

Edited by rickyquicky on Monday 20th October 12:47

Edited by rickyquicky on Monday 20th October 12:48

[rickyquicky]

bigjobbo said:

I would first check fuel, spark and compression to eradicate the possibility. I have to ask, is it possible the battery was drained from trying to start the vehicle, and not the radio?

Hi, battery was definately drained due to the radio and lights being left on, the interior light was probably on, and her phone was on charge too most likely!

Just to add fuel and compression are confirmed ok too.

[SMB]

I suspect something was likely wrong before the 20 min the car was sat as that shouldn't drain a battery in that length of time, so perhaps an existing battery issue or alternator issue.

that said , I'd be surprised if that fried the ecu. sounds more likely that the in built immobiliser is not allowing the car to start.

can you hear the fuel pump prime when turning on the ignition?
try the spare key to see if the coding for one has been lost somehow
if you need to go further , I would expect you need more dealer level diags and systems. You will certainly need that if the ecu is truly past it.

[bigjobbo]

Check the lives and earths to the ECU. I've never seen an ECU blown by jump/boost starting a car, but there's always a first! A relay failure is more likely though, IIRC Main relay J271 feeds engine control module.

[darrain-u5a3a]

Hi was there an answer to this fix in the end cheers

[marcford86]

I've been to a couple of VW with this issue, if you turn the ignition on and remove a certain fuse from the under bonnet fuse box (think it's immobiliser or instrument cluster fuse - can't remember exactly which as I've got the info at home and I'm on holiday atm!) then refit it will fire into life as normal!

[chimaerachris]

marcford86 said:

I've been to a couple of VW with this issue, if you turn the ignition on and remove a certain fuse from the under bonnet fuse box (think it's immobiliser or instrument cluster fuse - can't remember exactly which as I've got the info at home and I'm on holiday atm!) then refit it will fire into life as normal!

Can you tell me which fuse it is please as I have one doing the same thing?

Thanks

[Christophergohvw]

marcford86 said:

I've been to a couple of VW with this issue, if you turn the ignition on and remove a certain fuse from the under bonnet fuse box (think it's immobiliser or instrument cluster fuse - can't remember exactly which as I've got the info at home and I'm on holiday atm!) then refit it will fire into life as normal!

Hi Marc

I’m not sure if you still use this forum. It looks like I have similar problem. Changed the battery on my VW golf and now the engine won’t fire up.

Have called around a few VW dealers with no joy. Just wondered if you could help point me in the right direction to getting in sorted.

All info much appreciated.

Thank you

Chris