browellm

Hi

Could you have a look what TIS says is "normal" operation for the standard cruise control. Mnay members here have said how well they think the cc works but I have found 2 problems

1) With the Auto box cc unnecessarily drops a gear to recover a previously set speed when, even only a small difference between the speeds. This causes a jolt of power.

2) When going downhill the car simply coasts, cc makes no attempt to keep the required speed through engine braking.

I'm not 100% sure on my s/w version but I suspect it is 11.2

PhilS

My 530d behaves in exactly the same way. If cruise is set for 65 and I increase it to 70, the car drops down and accelerates quite harshly to the new speed - far from smooth.

Doctor Diesel

I think thats just the nature of the beast, all my BMW's did that (except the manual ones)

jmcaiado

Hi,
I've been searching the TIS CD's (NOV 2003) and they don't cover Cruise control nor Active cruise control yet. I'm trying to get more recent TIS CD's...
From personal experience with acc, i know that the car does not down shift when i increment speed a little and, when going downhill, the speed is mantained.
Maybe the regular cc is less refined than acc!

PhilS

Kind of defeats the purpose of having an auto, but I guess switching to manual whilst on cruise on the motorway would alleviate this to an extent.

browellm

Yes, you're right PhilS, I have been using the "M6" workaround off and on.

Iceman

When the car drives downhill it should not speed up, but since the car can't use the brakes itself (only with ACC) it might become faster because of the weight rolling/pushing downhill. All the car can do is, to take the fuel away, but that is not enough braking though when going downhill.
This might be another point for buying the ACC, just like driving in bad weather conditions (fog, snow), where the radar can see more than the driver's eye.
I love using my ACC and haven't found any dislikes so far.

browellm

When the car drives downhill it should not speed up, but since the car can't use the brakes itself (only with ACC) it might become faster because of the weight rolling/pushing downhill. All the car can do is, to take the fuel away, but that is not enough braking though when going downhill.
This might be another point for buying the ACC, just like driving in bad weather conditions (fog, snow), where the radar can see more than the driver's eye.
I love using my ACC and haven't found any dislikes so far. [/quote]
Iceman,

The Steptronic SHOULD be able to drop a gear or two though, and use engine braking. This worked perfectly well on my previous Merc cruise control.