GTI DSG cut out at motorway speeds. Urgent help!!!!

[slynch23]

My girlfriend was driving the car today and as we were on a dual carriageway doing about 60 the gearbox started dropping gears and slowing the car down. I put the stick into manual and told her to change up with the paddles but it kept undoing it and dropping it down! Luckily there was a lay by coming up so we pulled in there and the car slowed itself to a complete stop and the engine cut out. My girlfriend said the throttle wasn’t responding at all when she was trying to speed back up. Anyway.. so I jumped into the drivers seat and tried to start the engine but it wouldn’t, no lights on the dash or anything apart from the battery light - we both unplugged our phones and tried again but still nothing. I think I got it to start on the 3rd or 4th attempt.I drove the rest of the way home (about 1hr 20mins) and it was absolutely fine. I’ve done nearly 400 miles in it this weekend and apart from that it’s been faultless.

My girlfriend needs the car for a 500 mile round trip on Thursday and I’m now absolutely terrified, especially as she’s 6 months pregnant.

Does anyone have any idea why this could have happened? Has anyone experienced it?

[GreigC]

Are you sure the car did not go into limp mode? rather than the issue being with the DSG. You need to scan the car for faults. I recon your issue is with the engine… most likely a sensor at fault.

[slynch23]

Sorry, the way I’ve worded it makes it sound like I think there’s an issue with the DSG - I don’t. I was just describing what exactly happened. I got the impression the car was dropping the gears to bring it to a halt.

If it went into limp mode would it have started back up with no issues? Cause I was wondering if it was limp mode..

It’s interesting you think it’s a sensor - I get the occasional smell of petrol from the car when I park up, I took it to a local vw specialist to have a look and they checked it over and said they couldn’t find a fault but it could be a lambda sensor or over fueling. They said to leave it an persevere for now but Im gonna have to get it looked at again. It won’t be any fun living with a car I can’t trust

[GreigC]

If the fault is intermittent and the car is protecting itself it will go into limp mode to prevent damage. When you turn the car off and then back on it might read the faulty sensor as being fine and start again until the issue comes back. I wouldn’t leave it as you were recommended the cars clearly telling you there is an issue. I would take the car to a local garage for diagnostic scan or buy yourself a cheap OBD reader. Once the codes have been read you will be able to diagnose your fault.

[slynch23]

Yeah I definitely won’t leave it, I’m going to get it looked at asap. What’s worrying me though is the guys at the specialists plugged it in and scanned it but no errors came up. So if that happens again I’m still in the same position of not knowing the problem

[pudding]

If it's a MK6, the two things I'd be outruling first:

1) Stretched chain/worn tensioner
2) Failed HPFP.  Look for the oil level being way above Max and stinking of petrol.

If none of the above and no fault codes, best get it into a garage for investigation.

[slynch23]

You were pretty much bang on Pudding.. the VW specialists plugged it in and said it had 2 fault codes relating to the HPFP but said they weren’t serious and cleared them. He said it could be a sign it’s on its way out or it could be because I had put normal 95ron petrol in it (usually put momentum in but couldnt get anything above 95 in the mountains of north wales haha). Really hoping it behaves itself for my girlfriend this weekend then I’m going to get it sorted

[pudding]

It won't be related to 95 RON, it's probably mechanically on it's way out.  The internal seals fail and leak petrol into the sump, which also massively reduces the pressure to the injectors....hence cutting out on your girlfriend.

I can't believe they just cleared the codes and sent you on your way.  You never, ever want to see any kind of fault code related to fuel delivery!

I would plan to replace the HPFP when you get a chance before it starts filling the sump with fuel 

[slynch23]

It’s absolutely fine now though. Apart from it going into limp mode briefly it drives perfect. It has none of the other symptoms relating to the HPFP failure either. I don’t know what to think to be honest haha