Cruise Control disengages by itself

[Hillman]

Hi All

Any ideas why the cruise control on my 2000 x reg e220 cdi would disengage itself? It's started to do this over the last few week. I can be on the M'way happy as larry on cruise then for no reason at all the cruise will go off. Not a whisper of break pedal or a touch of the stick!

I can reengage it and it will carry on happily! Any ideas?

Cheers

 

[David Nock]

No expert on this but I do remember a post on here a while back which suggested that the cruise might disengage if it picked up unequal rear wheel speeds, such as might be caused by one rear tyre worn more than the other.
Sorry if this is a red herring. Out of interest are all the tyres sound?

 

[bigasotonuk]

Have you changed any tyres lately? as david says this can cause the problem your experiencing.

 

[Hillman]

Now that is interesting as I have just had 2 brand new Goodyears fitted to the front of the car. The rear tyres are only 12 months old and seem fine. Measured the trad and they are the same depth. Could new tyres on the front cause this??

 

[bigasotonuk]

Are the tyre profiles the same as the ones that came off?
Also maybe worth checking the tyre pressures, as I have heard this can cause this but I have always doubted that the system would be that sensitive. Though later cars tyre pressures are monitored in a similar way.

 

[Tim Green]

If you look further down the page you will see a similar thread from me from about a week ago. A similar problem caused by two different pairs of tyres being fitted, with slightly different rolling circumferences. On my car the circumferences were only about 1 inch differenct and the problem occured. Try measuring with a length of string fully around the wheels and measure difference.

 

[JEZ.S320L]

Hi All

Any ideas why the cruise control on my 2000 x reg e220 cdi would disengage itself? It's started to do this over the last few week. I can be on the M'way happy as larry on cruise then for no reason at all the cruise will go off. Not a whisper of break pedal or a touch of the stick!

I can reengage it and it will carry on happily! Any ideas?

Cheers

Yep - Check tyre sizes & Makes.

Same problem as you. Chaged all 4 tyres to the same size and Make - no problems since.

 

[blackbeauty]

I experienced a similar promlem a couple of years ago and the MB diagnosis was.... wait for it... NEW GEARBOX, Rads and all that goes with it!!! fortunately that one was a warranty exercise.

 

[whitenemesis]

This could also be a faulty brake pedal switch. Much cheaper to replace!

 

[alec2]

This was a well known problem on the C class of the early 2000s. I do not know if it also applied to the e class.

A wiring modification was required under warranty.

Is this a new problem on your car or could it have been there all the time?

Alec

 

[Hillman]

Hi Alec

It's a new prb and I have done some more testing. CC works no probs at all until it gets to over 68mph. I'm going to have the tyres balancd again to see if this helps

Cheers

Paul

 

[JEZ.S320L]

Hi Alec

It's a new prb and I have done some more testing. CC works no probs at all until it gets to over 68mph. I'm going to have the tyres balancd again to see if this helps

Cheers

Paul

Have you checked that the tyre sizes are correct/match?

Can't see it being anything to do with balancing.

 

[alec2]

I agree with previous posters, the problem will probably turn out to be different tires on the front and rear.
Make sure your pressures are correct.

Alec