1.6D fast idle, not regen. DSG

Hello everyone, finally joined after a few years of reading!

Basically my DSG Mechatronics unit let go at 29500 miles, hyd pump failed. Vw fitted new unit (just in warranty, luckily) since having the new one fitted I have covered 1500 miles (enough learning time for new unit), the car continuously fast idles at 1000 rpm.

Vw have had the car 3 days, and they haven't got an answer why it's doing it.

Definitely not a mini regen, happens when car is in D and auto hold is holding the brakes, if I turn start stop off and keep foot on brake pedal, it idles at 800rpm. Feels like the gearbox is advancing throttle as if the auto hold is off, to take up drive!

It does this if engine is hot, cold, alternator under load, everything turned off

Only a small problem but bloody annoying!

Not a definitive but I'd scan it as it's always the best place to start.
Has it hill assist and a towbar fitted? I'd look to see if the car thinks it's about to pull off up hill or with a trailer and is bringing the idle up. Do the megatronics require any calibration via VCDS and not just driving data alone, people drive differently and therefore it could learn your ways but be stuck with mine.

Evo said:

Not a definitive but I'd scan it as it's always the best place to start.
Has it hill assist and a towbar fitted? I'd look to see if the car thinks it's about to pull off up hill or with a trailer and is bringing the idle up. Do the megatronics require any calibration via VCDS and not just driving data alone, people drive differently and therefore it could learn your ways but be stuck with mine.

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No towbar, and the only assist is the automatic brake hold. Although I know if it isn't holding fully it let's the clutch up slightly to stop the vehicle rolling. I know Vw had to code the new mechatronic unit to the car, and also to the key, as when we used the other key the car jolted and displayed 'gearbox fault' and wouldn't move. Again.

I'm going to have to get somebody to hook it up to VCDS, and see what they come back with