Weird gearbox, cruise control issue.

[davelevins]

Hi all, driving back home from NSW today I got a flat tire front left. As I only have a space saver I put it on back left and mover the back left to front left.

Car is my16 Golf Highline 110tdi wagon, 50,000kms dsg6.

For the rest of the drive I noticed a few things I’ve not noticed in almost 2 years of ownership.
Firstly, now the car seems to engine brake much heavier than I recall it ever doing. Like 3rd gear high revs with light braking, enough so that you feel the car pull up pretty clearly as it drops to 3rd.
Secondly, and more concerningly, activating cruise at 80km immediately selects 4th gear, then cruises at 4th. If I put dsg to manual the dash suggests shifting to 6th, and will do so fine. But pull lever back to D and car is back to 4th. That’s certainly never happened.
Finally I swear the car became rear drive with a noisy tail shaft because the road noise was very loud, I swear when coasting I could here the tire rolling and it sounded like a noisy diff in the rear... I’m assuming that’s just the hard spare tire at high psi (sidewall said max 60psi, had 52psi in it when I checked). Seems so high to me.

A google search has shown me the engine braking thing is normal but I swear I’ve never noticed it. It’s the cruise control thing that has me worried. Car was definitely in D not S, it’s as if the ECU thought I was towing. I have no tow pack fitted.

due for 45km service I’ve just been busy and broke over Xmas.

[crainger]

Would the space saver have extra rolling resistance and increase the feel of engine braking and cause the CC to think it's towing?

[gregozedobe]

The space saver spare tyre was 8 psi under-inflated, which would reduce its effective rolling diameter, maybe that was confusing the cars various electronic brains ?

[Hillbilly]

Maybe the ABS is upset with the different tyre diameter You should probably have recalibrated it when You put the spacesaver on and maybe it is braking harder as it thinks there is a problem

[davelevins]

It's in getting a replacement tyre today. So hopefully when I pick it up all is back to normal. The rolling diameter of the wheel is certainly smaller than the 225/45/r17s the Highline comes with. So the above answers could be (and hopefully are) correct.

[Valvster]

It's in getting a replacement tyre today. So hopefully when I pick it up all is back to normal. The rolling diameter of the wheel is certainly smaller than the 225/45/r17s the Highline comes with. So the above answers could be (and hopefully are) correct.

My local tyre shop owner has a Golf and the first thing he did was source a 15" rim and put a 175/65/15 (I think ) tyre on it. He tells me it fits the space were the space-saver tyre goes and allows you to drive home at the speed limit rather than the speed restricted S-S Tyre.

Valvster