ACC and Start Stop not working

[glen290]

Had my GTI in the dealers yesterday for a new battery and DSG oil change, my partner picked it up and they said that there are a few error codes they couldn't clear and to take it back in for investigation.
Turns out these error codes are that my ACC and start stop no longer working, all was fine before I took the car in to them for the 2 jobs I needed

[clubsport]

I fitted a new battery on my GTi yesterday.

It is fun & games, you have to use an OBD coder, Vagcom , OBDeleven for example.

You have to set the car to recognise the new battery, they obviously did that or the car will not start.

Straight away you will have a dashboard full of lights and various "bong" sounds, plus a handful of error codes pop up.

As you drive the car and some (not all) will disappear more or less instantly.

For the ACC & stop start, you have to drive for 5-10mins then clear the codes, it seems to think it has not got a correct signal or input from the system.

As I said, I did this, then cleared the codes, ACC & Stop start is back working fine.

I re-ran a scan and have the all clear with zero error codes shown.

It is a pain, but once you have cleared and got the car back to where it was, you should have no recurring issues.

[glen290]

Went out for a 40 minute run and tried to clear the codes with Carista last night, still have the same issues..

[clubsport]

I don't know Carista well enough, do you know anyone with a Vagcom, OBD11 ?

It sounds like the same issues after a battery change, it sort of makes sense that the Acc camera needs to see a change of scenery before reset?

[mcmaddy]

Why have the garage given you the car back when it's not really roadworthy from a safety point of view??

[fredgroves]

Why have the garage given you the car back when it's not really roadworthy from a safety point of view??

ACC and start stop not working isn't going to cause a safety issue.

Its a quality issue though and I am sure they know that these suffer as above when the battery is replaced - the mk7 is 7 years old now.

They should have done the ten minute test drive.

[mcmaddy]

Will the city braking system still work without ACC being active? Just seems very poor customer service either way though.

[fredgroves]

Will the city braking system still work without ACC being active?

If it says "front assist not available" or similar then yes city braking (aka "front assist") would be not working.

AFAIK its a different subsystem.

[glen290]

Update on my gti, its been back in to the dealers today with the service guy quoting this morning, if it shows as a historical issue, then I would be charged.
Got a call about 1 saying car was sorted, the tech who did the coding hadnt done it correctly and all was ok now.
There are still a couple of error codes showing but thats down to having a MIB2 fitted and not the original MIB 1.