Mk5 gti electrical nightmare

Try to explain what's happening.this is my daughter recently purchased gti dsg.
Well looked after car with history and mostly vw history not a ragged abused car imo.
Sat night she calls to say her airbag light
Illuminated first.she pulled over turned off engine restarted and just about every warning light on dash illuminated with the annoying ping.all dash lights were orange except one that went to red.that was the steering wheel icon but that initially was orange.spoke to someone and he said to try voltage check done that and is reading 13.8v with engine running and everything on.also said disconnect battery for one hour/reconnect/lock unlock twice/wait ten seconds and restart.this improved things but only for a short time.before back to same state as before.the only change was that the steering wheel icon was orange then went red but still with all other orange icons.temp needle dipping and rising and also the rev counter(quite dramatic)movements also the autobox symbol on dash would flash.but didnt strait away after the battery disconnect.
In fact I did just select "d" felt the gear engage but wasnt going anywhere with all this going on.im at a loss completly.

 

Car was recovered home.aa man sent me this. g
Bizarrely with all this the car still starts.

 

Bit of a stab in the dark, water ingress somewhere, or battery connection?

 

Could be battery/power related.
Measure the resistance between can l and h, should be about 60ohms battery off(no can-bus communication).

 

They're known for bad connections at the battery fuse box.

 

Bit beyond me are electrics got a multimeter
But what is can1 and h dont know what that is.lol.
So does it look like some sort of complete power failure or something.
Checked for wet carpets etc and nothing as wet electrics are never a good thing.
Is there anything to check at scuttle area?
I'm ok with mk1,s and 2s but out of my depth with electrics in a mk5.

 

Can-bus is a network modules can communicate, has 2 wires twisted can-low and can-high.
Check connections on engine comp fusebox.

 

Ok thanks mk5s different to what I'm used to.
I've had that fuse cover of but dont really know where look.will look for them wires and check.
The aa man said he thinks the ecu is knackered.i said hows it still starting if that was the case wouldnt that ecu control.fuel,spark
Timing etc.

 

As most if not all codes are lack of comms,could be the can gateway, its a seperate module near the pedals.

 

Does the Mk5 have one of those 'clock springs' around the the steering column/wheel? My 2012 Passat Estate also lit up like a Christmas tree and it turned out to be that and it is a common issue with the Passat (according to local main dealer anyway)

 

it will have but that would only account for the airbag/steering wheel electronics not the faults with nearly every module on the car.

 

If you need to remove the gateway here is some info https://www.mk5golfgti.co.uk/forum/index.php?topic=47405.0

 

Latest is I use a trusted mobile mechanic who is reasonably cheap.he used his what he said is newest device whatever that is.
He said hes checked everything and can only come to the conclusion the ECU is gone.
Took it out there is evidence of water staining on it and at least 3 pins were corroded green.he recommended sending the ecu off to" the ecu doctor "in Plymouth.
So that's where I'm at(no choice)and running out of things to check.but hes convinced its shot.he gave me a print out of what he found.
Similar to before tbh..this is my daughters car and not had it long.she is gutted but being her first proper quick car she has concerns.my gut feeling is it's a good looked after car and it's just bad luck at a bad time.dont believe it was mis-sold to her.if ecu is serviceable its £245+vat for a replacement £345+vat.at least if were starting with a good/right ecu the rest if anything should flag up.she bought the car private very recently (I WENT WITH HER)I test drove the car no warning lights and drove near hundred miles home no issues! a few more short trips and then wallop all the crap started.wouldnt have thought an electrical issue could be masked unless your very clever.ive contacted
Seller and hes surprised at the fault and is willing to contribute to an ecu.

 

Good luck, hope that fixes it. Looks a tidy car.

I would have thought it wouldn't run with water ingress into the ECU but you said it runs originally?

 

Fingers crossed it gets sorted,
When kids were smaller we had a ford galaxy and that suddenly started being a pig , could drive to sainsbury's about 2 miles, then it wouldn't start afterwards for about 10 tries, had it diagnosed by ford on about 4 occasions and couldn't find anything, then one day it just died, AA said fuel pump so got towed to local garage, they said same, replaced £300 bill, went to pick it up and it didn't start, tried several other things, then my mate at the scrapyard suggested fusebox on them is a bit iffy.
Electrical problems are a nightmare, that's a nice golf, good luck with it.

Have you looked at plug and play ecu on Ebay, around 130 quid?

 

It's not mine it's my daughters first gti too.
She only 21 and dont know much.was thinking of mk5 myself but after her getting
This I'm a bit put off tbh(maybe oneday)when I've sorted and forgot this nightmare.the only good thing is I dont think she paid over the odds for it.£4300 112k vag history to 75k.
Dsg and heated leather.think if she can sort this car for under a grand it will be still in the right money imo.and they are rising.so not all doom and gloom.she lives for cars lol dont drink or smoke just likes nice things.a bit of a leap for her too she gone from a 1.4 auto polo 75bhp.to a 200bhp golf she looked scared to death when she first drove it.lol

 

Latest is the ecu has been sent away and bench testing the result has been confirmed their is (no fault).
Now where do I go from here I am at a loss.
Dont know what to check.

 

One thought would be to remove control modules that have communication errors and check if the errors go away, one module at a time. This can be hard and requires access to modules connectors.
Another thought is pick a module from listed errors, easily accessible and confirm the module has power/ground just to rule that out.
Here are some wiring schematics for a 2.0 fsi 147

 

I agree with @GVK, sounds like CAN gateway. For some background, MK5's have 3 CAN busses, powertrain/drivetrain, comfort and infotainment. You have issues with at least drivetrain and looking at that, the other two as well. chances of all of those wires failing or modules failings is basically zero, unless there was huge electrical issue (battery connected backwards level of destruction)

The gateway handles all communication between the diagnostic tool and the cars network so is very important that it works correctly