s350 (2003 reg) cruise control problem

[crc12]

Looking for guidance

Used to have c180 which was fine including cruise
Got a s350 2003 reg - cruise doesn't work above 47 mph
Can cruise at 47mph...If I try cruising above that speed cruising speed drops off with flashing light on speedometer...not sure what is the issue.
Also unfamiliar with the car controls
Any suggestions/links to previous discussions/advice welcome

 

[Blobcat]

Hello and welcome

There will be a diameter difference between some of the wheels causing a speed imbalance to the system.
Have you different sized wheels / tyres front to back? Are any of them low on pressure?
Also you might have an issue with the speed sensors on the wheels - rusted reluctor rings is quite common.

 

[crc12]

Thank you...got it last weekend...don't know if wheels were swapped... Can check tyre pressures...strange that able to cruise at lower speeds but not motorway speeds (do lot of motorway miles)

 

[crc12]

Thank you...got it last weekend...don't know if wheels were swapped... Can check tyre pressures...strange that able to cruise at lower speeds but not motorway speeds (do lot of motorway miles)

It was basic....
Tyre pressure on a front wheel was low...Once corrected cruise works fine... Never had that problem with c180 despite varying tyre pressures..

 

[Blobcat]

It was basic....
Tyre pressure on a front wheel was low...Once corrected cruise works fine... Never had that problem with c180 despite varying tyre pressures..

Simple fixes are good

 

[crc12]

Simple fixes are good

I thought so...took it for a motorway drive
Same problem..cruising upto 47MPH no problem...after that cruise engages for few seconds and drops off
not sure why?

 

[crc12]

Are there any experts on cruise control problems in the forum for advice?

Took the car to independent merc.service
They haven't come across a situation where cruise cuts off at 47 mph
Cruise can't be used on motorway speeds.

Any advice on fixing this apart from taking to the main dealership?

 

[Wighty]

Are there any experts on cruise control problems in the forum for advice?

Took the car to independent merc.service
They haven't come across a situation where cruise cuts off at 47 mph
Cruise can't be used on motorway speeds.

Any advice on fixing this apart from taking to the main dealership?

Which independent Merc did you take it to buddy , and what area do you live in ?

 

[crc12]

Birmingham..

 

[mersum1es]

And all tyres are same size, and brand, originally? That sound just speed difference limit is triggered. Live data would tell....

 

[LostKiwi]

^^^^^ this ^^^^^

 

[crc12]

Thanks Tyres original, tyre pressures checked
How to overcome the speed difference limit.??
Live data while driving??