Desperately need help

[nath86]

My o7 plate cupra has developed the following issue.
Started with trying to start the car with nothing shown on dash.. car stated and immediately cut out x3 time. Removed battery to charge incase this was the cause.
Replaced battery now still nothing on dash and car will not turn over.
Terminal 30 and 15 relays seem ok on voltmeter readings across the pins. Just swapped out dash cluster with another as I thought it could be immobiliser fault..still no change...
Does any one have any idea or had the same/similar issue

 

[R3k1355]

Have you read fault codes with VCDS or similar?

 

[nath86]

Garage across the road from me tried. But it was struggling to connect properly. What it did manage to connect to it threw up a load of low voltage codes

 

[R3k1355]

Stick a decent battery on it and get the codes read properly, otherwise no-one can help you.

 

[nath86]

That's the thing though... battery's only 6 months old and fully charged..everything else on the car light,wipers 12v socket etc all work fine

 

[R3k1355]

You've checked all your battery cables and all the earth points?

Dodgy earth near the ECU can give it problems.

 

[nath86]

Earth are my next port of call.... how many are there..do you know?

 

[R3k1355]

I don't know, but the main battery earth and the one nearest the ECU would be first to check.
Check the condition of the wires and connectors as well, they might look ok at a glance but could easily be frayed or badly corroded.

If there's any electrical tape on it that shouldn't normally be there, peel it off and see what's going on.
This is the condition I found the negative lead of my Evo in.

 

[mty12345]

Low voltage codes are just from having a flat battery. Just delete them and see what else comes back. If the garage doesn't know that, then i'd take it somewhere else. Plenty of good mechanics who are absolutely terrible at diagnostics, I see it time and time again.

The fact it starts and just cuts out sounds like immobiliser fault. If you swap the cluster it needs to be coded to the ECU and Key, unless you've done that i would swap back to the original cluster.

As said, without fault codes/live data, you won't be able to solve it. If the scanner won't connect then it's probably a CAN-BUS type fault. In that case take it to a VAG specialist or auto-electrician.

 

[nath86]

Thanks for the response guys... much appreciated
Got some free time tomorrow so weather dependent I'll have a look at the earth's and go from there. It only did the starting/cutting out 3/4times now it won't start at all