2019 chassis cruise control issue

Coach06

19/19 Unity MB
This sounds similar to an issue I had when I picked up my 2019/2019 CB from Sacramento the other month, almost certainly before you. I had a message saying "Active Brake Assist disabled" or something like that.

I took it to MB of Fairfield and they updated the software. All fine now and 2,500 miles in.

Chris
Chris.. I have now had our 19/19 U24MB to three separate Mercedes dealers without a fix for our cruise control issue. I see below (message #18) that Widman has the same issue and Fairfield was NOT able to fix it. Widman now has an appointment (message #20) with Mercedes of Santa Rosa for the repair. do you have any information on your invoice/paperwork that would provide the software update that corrected your cruise control issue?
thanks
BruceC
 

Coach06

19/19 Unity MB
Fairfield did not fix the cruise or could they fix the seat adjust. They did not have a clue, then called me 3 days later to say they could fix the seat adjust for $85! I have an appt at Santa Rosa MB, who are aware of both issues and could adjust.
Please obtain some detail on how they fix the cruise control... ie: bulletin number, software update revision number, etc. I will pass it along to the Fresno Mercedes dealer where our Unity now resides and perhaps they can obtain the same instructions for a cure.
Thanks
BruceC
 

Widman

Member
Please obtain some detail on how they fix the cruise control... ie: bulletin number, software update revision number, etc. I will pass it along to the Fresno Mercedes dealer where our Unity now resides and perhaps they can obtain the same instructions for a cure.
Thanks
BruceC
Mercedes Santa Rosa fixed the seat back but could not fix the cruise control. Since there is a sensor in the seat that disengages the cruise if you lift off the seat, they could not disconnect.
I just have to keep my but planted on the seat cushion.
 

Coach06

19/19 Unity MB
Mercedes Santa Rosa fixed the seat back but could not fix the cruise control. Since there is a sensor in the seat that disengages the cruise if you lift off the seat, they could not disconnect.
I just have to keep my but planted on the seat cushion.
Thanks Widman.. Just to make sure I am understanding you.. You do not see an erratic cruise control behavior except when you 'lift your butt off the seat'.. correct? Almost wish mine was that simple a fix.
Mercedes Fresno has received a new distance sensing 'module' and is installing it as I am writing this message. Will let you all know if this solves my erratic behavior (mine also disengages when lifting off the seat).
 

mscarcella

New member
Resolved ever since I removed the “Purple Gel” seat cushion I’d been using... I can duplicate the error message by lifting my rear end off the seat. No problems since getting rid of the cushion.
 

Hogan

New member
Picked up a new 2020 Unity 24MB on the 2019 Chassis with all the safety bells and whistles. Drove it about 250 miles home so we had time to play with it. Had the same problem with my wife but not me. I weigh about 220lbs and she weighs about 115lbs. She is not heavy enough to keep the cruise control activated. Would pop off with error message "Active Distance Assist Canceled" after about 5 seconds to 5 minutes. She must be just almost heavy enough to keep it activated.
Called MB Customer Service and got the "cant adjust a safety device explanation." Talked to my local dealer and he promised to investigate and respond if he learns anything.

Seems like overkill safety.

Lst me know if there is any type of fix available.

Thanks
Hogan
 

Coach06

19/19 Unity MB
Picked up a new 2020 Unity 24MB on the 2019 Chassis with all the safety bells and whistles. Drove it about 250 miles home so we had time to play with it. Had the same problem with my wife but not me. I weigh about 220lbs and she weighs about 115lbs. She is not heavy enough to keep the cruise control activated. Would pop off with error message "Active Distance Assist Canceled" after about 5 seconds to 5 minutes. She must be just almost heavy enough to keep it activated.
Called MB Customer Service and got the "cant adjust a safety device explanation." Talked to my local dealer and he promised to investigate and respond if he learns anything.

Seems like overkill safety.

Lst me know if there is any type of fix available.

Thanks
Hogan
Thanks for posting Hogan. Forgot I committed to posting after retrieving my Unity from Fresno Mercedes. No joy. The cruise control is still erratic and gives the "Active Distance Assist Canceled“ message. I also notice if I adjust my position on the seat it disengages. If I sneeze loudly, it will disengage... obviously seat sensor.
Mine also has an interesting quirk, the ‘limit’ icon in the center screen will only display the legal truck speed not the posted speed for all other vehicles. We live in CA where multiple axle vehicles are limited to 55 mph. That is the maximum number it displays. I am thinking perhaps my Sprinter also has a software issue..
Does anyone else have this speed limit ‘error,?
 
Thanks for posting Hogan. Forgot I committed to posting after retrieving my Unity from Fresno Mercedes. No joy. The cruise control is still erratic and gives the "Active Distance Assist Canceled“ message. I also notice if I adjust my position on the seat it disengages. If I sneeze loudly, it will disengage... obviously seat sensor.
Mine also has an interesting quirk, the ‘limit’ icon in the center screen will only display the legal truck speed not the posted speed for all other vehicles. We live in CA where multiple axle vehicles are limited to 55 mph. That is the maximum number it displays. I am thinking perhaps my Sprinter also has a software issue..
Does anyone else have this speed limit ‘error,?
Yes, I have similar confusing operation of the speed limit assist feature. It is obviously reading roadside signs. I have seen it change the display when entering a construction zone with temporary speed limit signs. But on limited access freeways it frequently shows lower than the speed limit on the sign just passed. I haven’t yet figured any pattern to the madness.
 

Coach06

19/19 Unity MB
Yes, I have similar confusing operation of the speed limit assist feature. It is obviously reading roadside signs. I have seen it change the display when entering a construction zone with temporary speed limit signs. But on limited access freeways it frequently shows lower than the speed limit on the sign just passed. I haven’t yet figured any pattern to the madness.
Hey Shadow.. Two separate MB Sprinter dealers have informed me that our Vans are considered trucks - and the Sprinter will register the truck speed limit when on the freeway/highway. Hard to believe but there must be a vehicle registration code that requires that designation.
 
Hey Shadow.. Two separate MB Sprinter dealers have informed me that our Vans are considered trucks - and the Sprinter will register the truck speed limit when on the freeway/highway. Hard to believe but there must be a vehicle registration code that requires that designation.
I can believe that - anything over 10,000lbs GVWR is a truck. Will be interesting to see what it does when I head west on I-10 soon - speed limit 80! That is also the truck limit in west Texas.
 

Coach06

19/19 Unity MB
I can believe that - anything over 10,000lbs GVWR is a truck. Will be interesting to see what it does when I head west on I-10 soon - speed limit 80! That is also the truck limit in west Texas.
Hey Shadow.. I think you will find the limit icon will indicate the truck speed limit for whichever state you are traveling through. If the speed limit in TX is 80MPH with no designator for trucks, you should see 80 in the limit icon. Please pass along your finding.
 
Back with an update for this thread. When driving in Texas, my 2019 chassis is never showing higher than 65MPH on the speed limit assist regardless of the road speed limit. This includes on interstates posted at 80MPH. As best I can tell from some Googling, the heavy truck speed limit in Texas is 75MPH. So it appears not to be working correctly here. It’s as if the database through which the speed limit signs are filtered is not correct.
 

bobtuba

2020 LTV Unity MB
Back with an update for this thread. When driving in Texas, my 2019 chassis is never showing higher than 65MPH on the speed limit assist regardless of the road speed limit. This includes on interstates posted at 80MPH. As best I can tell from some Googling, the heavy truck speed limit in Texas is 75MPH. So it appears not to be working correctly here. It’s as if the database through which the speed limit signs are filtered is not correct.
I noticed the same thing in east Texas. It never showed me 75.
 

2yrs2go

2019 Unity MB
Back with an update for this thread. When driving in Texas, my 2019 chassis is never showing higher than 65MPH on the speed limit assist regardless of the road speed limit. This includes on interstates posted at 80MPH. As best I can tell from some Googling, the heavy truck speed limit in Texas is 75MPH. So it appears not to be working correctly here. It’s as if the database through which the speed limit signs are filtered is not correct.
I've noticed something odd about the displayed posted speed limit too. On I66 west of DC it never shows the 70mph limit as the highway is in the more rural areas, it never shows more than 65mph. This is in VA, so I was also thinking it must have something to do with either truck limits or a programmed top limit in the MB software, then as I drove south into NC, GA, AL and FL it would display 70 whenever the signs showed that speed. Last night I was coming back into VA on I95 and there is an area south of Richmond with the posted speed is 70 and that's what was displayed on the Sprinter's display. So that mystery continues.

I'd also like to comment on this earlier post on the cruise control issues,

"Picked up a new 2020 Unity 24MB on the 2019 Chassis with all the safety bells and whistles. Drove it about 250 miles home so we had time to play with it. Had the same problem with my wife but not me. I weigh about 220lbs and she weighs about 115lbs. She is not heavy enough to keep the cruise control activated. Would pop off with error message "Active Distance Assist Canceled" after about 5 seconds to 5 minutes. She must be just almost heavy enough to keep it activated.
Called MB Customer Service and got the "cant adjust a safety device explanation." Talked to my local dealer and he promised to investigate and respond if he learns anything. "

I would definitely call BS on the answers you got. The seat sensor is a major part of the safety system in any new car and the weight of the occupant of the seat determines how the air bags deploy and the seat belt works in case of an accident. If they're telling you that your wife's weight is not enough to use the cruise control I would certainly want to make sure it is enough to trigger all the other safety features that are installed. Tell them that you are going to make an inquiry with the NTSB (I think they are responsible for vehicle safety, if not do a google search), to make sure the feds are aware of this possible safety deficiency. The cost of replying to one of those should light a fire under their butts. At least it would force them to actually post the lower weight limits of this feature. Good Luck
 

Hogan

New member
In a little late on this post but had a similar issue. Picked up 2020 24mb on 16 Oct. and drove 250 miles home. Cruise worked fine for me but would either not set for wife or fault out promptly after she had it set.
Did some research and found there is a seat occupancy sensor in the drivers seat that will not allow cruise to work if seat is not occupied. I weight almost twice what my wife weighs so we figured that was the issue. By spec talking with service it requires 65 lbs to be activated. wife weighs far more that 65lbs so we figured it was because LTV reupholsters seats with their fabric.

Solution was (not a good one by the way ) to take a seat cushion (bow hunting tree stand cushion ) and add 25 lbs of lead shotgun shot and place on drivers seat when she was driving.
Bingo! it worked.

We left for AZ. on 20 Oct from Iowa and about 1500 miles into the trip whe tried it without the weighted seat cushion. Walah it was fine. I assume the upholstery relaxed enough so the tension was not supporting the majority of my wifes weight.

Hope yours is as simple as mine
 

emondeau

New member
I've noticed something odd about the displayed posted speed limit too. On I66 west of DC it never shows the 70mph limit as the highway is in the more rural areas, it never shows more than 65mph. This is in VA, so I was also thinking it must have something to do with either truck limits or a programmed top limit in the MB software, then as I drove south into NC, GA, AL and FL it would display 70 whenever the signs showed that speed. Last night I was coming back into VA on I95 and there is an area south of Richmond with the posted speed is 70 and that's what was displayed on the Sprinter's display. So that mystery continues.

I'd also like to comment on this earlier post on the cruise control issues,

"Picked up a new 2020 Unity 24MB on the 2019 Chassis with all the safety bells and whistles. Drove it about 250 miles home so we had time to play with it. Had the same problem with my wife but not me. I weigh about 220lbs and she weighs about 115lbs. She is not heavy enough to keep the cruise control activated. Would pop off with error message "Active Distance Assist Canceled" after about 5 seconds to 5 minutes. She must be just almost heavy enough to keep it activated.
Called MB Customer Service and got the "cant adjust a safety device explanation." Talked to my local dealer and he promised to investigate and respond if he learns anything. "

I would definitely call BS on the answers you got. The seat sensor is a major part of the safety system in any new car and the weight of the occupant of the seat determines how the air bags deploy and the seat belt works in case of an accident. If they're telling you that your wife's weight is not enough to use the cruise control I would certainly want to make sure it is enough to trigger all the other safety features that are installed. Tell them that you are going to make an inquiry with the NTSB (I think they are responsible for vehicle safety, if not do a google search), to make sure the feds are aware of this possible safety deficiency. The cost of replying to one of those should light a fire under their butts. At least it would force them to actually post the lower weight limits of this feature. Good Luck
Did you ever figure out why the speed limit was off? We live in California and started to notice that recently - it always reads speed limit 55, when it should be 65. That was not the case when we acquired it in March 2020. I wonder if I pushed a button on the steering wheel that did something?
 

bobtuba

2020 LTV Unity MB
I have never seen greater than 55. There are signs out there bigger than Dallas displaying 60, 65 or 70 mph... and in Texas even some 75s. The display stays on 55 regardless.
 

2yrs2go

2019 Unity MB
Did you ever figure out why the speed limit was off? We live in California and started to notice that recently - it always reads speed limit 55, when it should be 65. That was not the case when we acquired it in March 2020. I wonder if I pushed a button on the steering wheel that did something?
Nope, really haven't been driving enough to pay attention. I've been stuck in Florida moochdocking due to the Covid situation, planning to head back north next week if I can find reservations in enough campgrounds to allow me to make the trip. That appears to be the biggest concern I'm going to have over the next few months. Along with replaceing the broken door latch on my coach door (just got the replacement yesterday). The cruise control and many of the other features(?) on the MBUX system have been moved to my "annoying things I have learned to live with" list.
 
I have seen it show as high as 75MPH. I think that was in Michigan. But here in Texas it never shows more than 65.

I think (i.e. guess) what it does is read the roadside speed limit sign, then filter the value by looking up a value for the maximum truck speed at your present location. If the limit is higher than the maximum, you see the maximum.

As best I can figure, here in Texas the limit for class 3 and larger trucks is 75MPH. So the implementation seems a bit suspect.
 

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