Cruise Control 2002 S430 unique issue

[khatm]

Hi everyone,

I have a 2002 S430 whose cruise control works PERFECTLY at 51 MPH or less. However, once reaching 52 MPH or higher, the LED bars around the speedometer blink and the cruise control disengages.

It doesn't matter if I accelerate to any speed 52 or above (let's say 70 MPH for example), then try to engage the cruise control, or if I engage the cruise control at say 40 MPH then use the cruise control lever to try to accelerate to 70. It ALWAYS disengages at 52, the bars around the speedometer blink and the cruise control disengages.

The tire sizes all match and the tire pressure is dead on. Again all functions (accelerate, decelerate, resume, etc.) work PERFECTLY at the lower speeds 100 % of the time. And 100% of the time, I get the same result above 52 MPH.

It all worked perfectly until about a week ago. I first noticed a problem when I engaged it on an entrace ramp, and used the cruise accelerate feature to get up to speed, then had to immediately toggle to decelerate to accomodate traffic. I braked during the decelerate so I could merge with traffic. I believe that's the last time it worked correctly (at speeds over 52 MPH anyway).

Did I stumble on some cruise control lever sequence that set a "top limit" for the cruise control feature accidentally? If so, how do I fix it?

Thanks in advance! I'm certainly stumped on this one!

[mbdoc]

Most likely related to tire SIZE. Measuring the circumference would confirm that problem

[khatm]

That's amazing! Let me see if more information changes things or not. It's the same tires (Michelin Destiny 215 60R16) that I've had on for about 65,000 miles...

I did just have them rotated and re-balanced at Discount Tire, and the shop said I should get at least another 15,000 miles out of them.

On a side note, these have been GREAT tires... quiet, great ride, better wet and winter traction, and double the expected mileage from wear as compared to the previous Michelin Energy MXV4 Plus.

Could it really be that decreased circumference from tire wear could cause the cruise control to stop working??? Strangely enough though, the problem did start immediately after the tire rotation, so if after the additional info you stand by your diagnosis, I totally believe you and already think you're a genius for the very train of thought!

Thanks for the help and please let me know if I should change out the tires. Was going to do wait until Fall for that, but not if it will fix the cruise control.

Also, are the Michelin Destiny's a good choice for next time? Winter traction is VERY important here is snowy Michigan, followed by quiet, ride, and somewhat less importantly, life of the tire and price.

THANKS AGAIN!