Engine not returning to idle when foot off the gas.

[DaveCrampton]

I have a 2017 Shuttle DSG. For the last two years when I drive along, if coasting down hill, when my foot comes off the accelerator, the engine speed returns to idle on the rev counter. This is when driving in auto, not knocked over to 'manual'. Then when my foot goes back on, the engine speed picks up again.
Now my missus has returned from her week away to Devon (we live in Scotland) she reports a light out, and sure, on the dash, there is an illuminated light symbol lit, but I also noticed that when I cruise with my foot off the gas, the engine stays on the revs it would, if I had my foot on the accelerator.

I'll be booking it into my garage Monday, but I wondered if any other DSG driver's have had this, and know what the problem was? It's nothing crazy is it? Where certain functions are disabled if there is a fault, like a light out...
Van drives fine, cruise control works fine, no outward symptoms of any trouble. I'm away to France in a month and I don't want the van to break down whilst I'm away.

Many thanks.

 

[keith baker]

Is the "coasting" option still enabled in the MFD?

 

[Oceanis]

Which light is out?

Could well be a coincidence and the faults are not connected.

Classic problems that would prevent your engine from returning to idle properly are a fault in the detection of throttle position, an air-leak in the inlet manifold somewhere, a fault in the idle-speed control system, a faulty temperature sensor making the ECU think the engine is cold ... there are also many other possibilities.

I'm sure the dealer will find the fault once he gets the diagnostic kit hooked up.

 

[Scottish Scrutineer]

It does seem that the coasting function is disabled for some reason. It might be linked to the fault showing. I have Carista to quickly check codes, or can see if VCDS throws up something. Give me a shout on Messenger or mobile.

 

[Deaky]

The bulb out warning would not cause coasting to not work. Could you have been in sport on the gearbox?, coasting doesn’t work in this mode or as others have said it may be switched off

 

[DaveCrampton]

Keith Baker had it. My missus (yes I'm going to blame her) took the Shuttle on holiday to Devon and was phoning me asking how to reset the tyre pressure sensor as she thought one was low so topped it up and was fiddling in the settings whilst she was away.