Intermittent cruise control

[Valps]

Can anyone throw any light on my fault?

As I drive along in my W210 2.4 the cruise works fine, and tends to stay working at lower speeds. When I speed up and reset the cruise it engages fine, but soon the car gives an enormous "miss" - only for a moment, the cruise disengages, the car drives fine but I cannot re-engage. I cannot re-engage cruise now unless I turn off the ignition and start the engine again.

Is it operated by some sort of vacuum affair in conjunction with the ignition?

I'm doing hundreds of motorway miles on an ongoing basis, and find it difficult to sleep if I have to concentrate on keeping my foot on the accelerator.

 

[230K]

Hi

What started it messing about? Do you have staggered wheels? Do you have worn tyres on front and new on rear? Are all tyres the same size??

230K

 

[Howard]

Valps , have you got non standard wheels ?

 

[PeterE320Cdi]

I have something similair to this, I have standard wheels with the same size tyres all round.

Sometimes it works sometimes not, once it is working it keeps working though rather then cutting out.

 

[GazCaff]

Maybe your brake switch is on its way out?

 

[Valps]

Thanks for your answers guys.

The wheels are standard 16", and have not been modified in any way. Literally one day it was fine, next day it started misbehaving.

It's this "miss" that interests me. It's accompanied by a sound a bit like a tyre being let down, then the cruise is disabled.

Maybe it's like other things on the car they sometimes sort themselves out. We'll see.

 

[BenzComander]

Maybe your brake switch is on its way out?

Would agree, dodgy brake light switch.

 

[PeterE320Cdi]

I had a new brake switch fitted yestarday but still have a problem with the cruise control working intermittently.

Has anyone got a suggestion on what to try next?

 

[rs2000]

Are all of your tyres of the same make and tread depth. I had a similar problem with my W203 after replacing the rear tyres - the fronts were down to 2.5mm. The cruise wouldn't work reliably over about 60mph. Months later and after the front tyres were replaced, the problem went away and it's been fine since.

 

[PeterE320Cdi]

Hi rs2000

Thanks for the reply. I had 4 new tires fitted a few weeks ago, they are the same size/width all round.

Peter

 

[prprandall51]

Incorrect tyre pressures could also affect the rolling radius....

 

[Dieselman]

It could be either a dirty/corroded hall effect ring on one wheel or a pickup sensor or cable going open circuit.

 

[PeterE320Cdi]

Having a new battery fitted seems to have cured my cruise control problem, not sure why it would have an effect though

 

[Flyer]

Having a new battery fitted seems to have cured my cruise control problem, not sure why it would have an effect though

Could it have simply been a hard reset (reboot?) of all the electronics after the brake switch was replaced?