w210 cruise control safety feature
 

the cruise control on the w210 seems to disengage if it senses going into a turn too fast...lately its been just shutting off at the slightest bend in the road. is there anyway to adjust this so its not so sensitive?

I am not aware of this "feature." Are you sure? Any documentation (owner's manual, forum threads, etc.) or just your own observations? Could it be a component or connector shifting position due to the G-forces imposed by the turn?

It shouldn't do that, at least mine never has. Maybe your cruise control stalk is faulty - ie, turn wheel, something gets disturbed, CC turns off?

I'll bet you a dime that your front and rear tires are not the same size. My car did exactly what you describe when I put snows on the back that were slightly different than the fronts. You must have the same size tires on all 4 wheels on these cars or strange things happen, including the "feature" you describe.

Also, check to make sure the tire inflation is correct. Your cruise disengages because it is sensing a differential between the front and rear wheels' speeds.

Check your wheels and report back.

its always done this..say driving in the mountians hwy and going into a gently turn it'll disengage.

its possible that the tires arent the same...225/45/17 and 245/40/17. the rears are worn down prety good. i'll put the stocker 16" set on and see what happens. it has always disengaged going through windy highways but now its shutting down just from a little movement.

i guess i cant put a 245/5017 on the rear to get better gearing?

Well, I am telling you that the reason it is doing this is BECAUSE your front and rear wheels are not turning at the same speed - have you always run mismatched tires on it? The ECU senses the slightest evidence of a "skid" and disengages the cruise. Mine did the same thing UNTIL I put a new set (all 4 matching) tires on it then it never did it again, EVER! The reason it only does it in a turn is because it doesn't go out of tolerance until you turn and the wheels on one side start turning faster than the other...then it trips the disengage order.

You're starting out with tires that are slightly smaller in back than in front, plus you have wear which makes them even smaller and turn even faster. I would bet you a dime if you went back to a matched set (size and type) it will stop disengaging on a turn. You can't even just match size, but size and type are critical because there is a tolerance between type/brands of the same size. The owner's manual is pretty clear too IIRC, it says use only a matched set of 4 tires on this car.

I have responded to this issue on here before, and every time using matched tires fixed it.

The only other common cause of CC problems is a faulty brake switch, but given your symptoms I would bet it is tires.

ASR or ESP will cancel the cruise if they detect any traction loss.

-Jason

I recall that the cruise control would disconnect itself if the speed dropped 10-15% while it was engaged. This was a fail-safe if the unit failed to disconnect when touching the brake as it is supposed to do. It is not difficult to apply enough brake force to slow the % required speed. Whatever mechanism or electronics effects this disconnect is out of spec or adjustment. If this is the problem, an MB or experienced indy may know how to fix it

it looks like an intermitting problem. i drove 250 miles and had all kinds of problems keeping it engaged..and drove 250 miles back on the same road zero problems..cruise control the whole way. i havent even changed the tires yet.

Well, when you want it to work 100% of the time all the time you know what you need to do, use the correct tires on all 4 wheels. For whatever reason you don't want to accept the fact that it is the tires causing your problem, but it is. The reason it isn't doing it all the time is because your tires are close, but not perfectly matched. I would bet if you added 5 psi to the fronts you would have even more trouble keeping it engaged.

I love it when people ask a question, they get a response and ignore it. Did you think it was a coincidence that I *guessed* you were running different tire sizes front and rear? This is a well documented issue with the W210 chassis.

Happy Motoring.

umkay. i posted it here to get opinions and experiences from more than one person also im not convinced that its a tire problem being that if i put the stockers on all having the exact same size bran new tires, the problem i described stays the same. not to mention that the wheelset i was using is a w210 staggered set with the factory recommended tire sizes.

happy motoring.