Cruise Control keeps dropping out? E280 W124

[JonGM]

My cruise control keeps dropping out?

I set it and it is fine for ages then allof a sudden it cuts out.

I then try and set it and it may work of a minute or so or NOT!

Before I start thinking about the ecu is there anything else that I should think about???

 

[tech lee]

hiya, just a thought, try checking tyre pressures and double check the tyre sizes are correct.

 

[MDMB69]

I have the same car, my cruise keeps surging up and down and occasionally dropping out.
I've replaced the speed sensor on the speedo, stripped the ECU and finally stripped down the throttle acuator.
I believe it is the actuator as it keeps buzzing with the ignition on before I start the car if you have the bonnet open. A lot of the wires in it have become brittle and the sheathing has come off. I believe the fault code read out is telling me thats what it is. The speed sensor and ECU in yours are probably fine as they are more reliable that earlier tempomat cruise systems pre 1994.
I may try to rewire mine but it doesn't look easy. A replacement is about £900 from the dealer, but I have heard of people getting them 2nd hand for around £100 although I haven't found 1 yet.