Lost cruise control on long trip

coss370

Active member
2019 here. I was using cruise control and all of a sudden I got the brake assist function limited message and I lost cruise control. Anyway to reset the car quickly without causing issues? I am 1500 miles from home
 

Kajtek1

2015 3500 X long limo RV
Are all the tires the model and wear, with the proper pressure in them?
If the tires are equal, the next thing to check would be wheel speed sensors.
It has to be pending error, or it would clear with ignition cycling.
 

GLJones

Active member
Sounds like your windshield or radar sensor got blocked by dirt, bugs or something. Usually, it will return in a few minutes or you can turn the van off and back on and it will reset. Make sure you clean the sensors. Window sensor is in the top center of the windshield in the black-out area. Radar sensor is in the vertical pillar in the center of the van inside the foot step in the front bumper area. Heavy rain or dirt can block it causing the issue you are experiencing.
 

coss370

Active member
I cleaned the windshield after it happened, cycled the car a few times and it was still there. After I made the post I started driving and everything went away. It took about 6 key cycles and 4 miles of driving
 

lizofwisconsin

New member
Coss370,

Did you ever have it happen again? I had it happen multiple times (3500 2020 sprinter). Found my answer in a post by rprochnow on Winnebago owners forum. Caused by driving too long with no vehicle in front. Apparently no feedback from the radar sensor causes computer to think radar sensor malfunctioning. Only fixed by following another vehicle for a few miles.

Rprochnow post

I live in a low population area, so happened kind of often, including 2 hours after 3.5 hour drive to Mercedes dealer where they replaced the radar sensor.

crazy design!
But thanks to Rprochnow, at least I know what to do when it happens now.
his idea is to try turning off cruise control for a short time every hour or so if in low traffic. I haven’t had a chance to try that yet
 

lickwid

Learner
It's happened to me, and it's usually when I've been driving on a long road trip. It can typically be fixed by wiping the windows and/or sensors on the bumper.
 

Roamers

2020 4X4 170 Crew
Caused by driving too long with no vehicle in front
Great find! This explains my drive in a winter storm with little traffic from Mid Nebraska to Loveland Co without cruise; only to have cruise re-enable after leaving the Interstate and driving in town for 15 minutes.

I had tried cleaning all sensors and restarting 3 times.

Nothing like learning idiosyncrasies!
 

lizofwisconsin

New member
It's happened to me, and it's usually when I've been driving on a long road trip. It can typically be fixed by wiping the windows and/or sensors on the bumper.
I know that can happen, and that is what the mechanic suggested when it recurred, but that did not fix it. My husband was laughing at me, madly scrubbing away at the bumper and windows in the driveway! Only driving to the highway and finding another vehicle to follow for about 3 miles fixed it! I am looking forward to seeing if it recurs on upcoming road trip and if the same fix works.
 

45Kevin

Well-known member
Coss370,

Did you ever have it happen again? I had it happen multiple times (3500 2020 sprinter). Found my answer in a post by rprochnow on Winnebago owners forum. Caused by driving too long with no vehicle in front. Apparently no feedback from the radar sensor causes computer to think radar sensor malfunctioning. Only fixed by following another vehicle for a few miles.

Rprochnow post

I live in a low population area, so happened kind of often, including 2 hours after 3.5 hour drive to Mercedes dealer where they replaced the radar sensor.

crazy design!
But thanks to Rprochnow, at least I know what to do when it happens now.
his idea is to try turning off cruise control for a short time every hour or so if in low traffic. I haven’t had a chance to try that yet
Interesting hypothesis.

I experienced the "disabled side assist and collision avoidance" several times on my long lonely trip across Canada recently. The cruise was never disabled and the message always eventually went away on its own. Most times not until I turned off the engine for some time.

I'll definitely take note of the traffic situation next time it occurs.
 

Boxster1971

2023 Sprinter 2500 144wb AWD
. . . I had it happen multiple times (3500 2020 sprinter). Found my answer in a post by rprochnow on Winnebago owners forum. Caused by driving too long with no vehicle in front. Apparently no feedback from the radar sensor causes computer to think radar sensor malfunctioning. Only fixed by following another vehicle for a few miles.
. . . crazy design!
Crazy design for sure!! I traveled this summer with a friend in a 2020 Tiffin Sprinter Class-C. He did OK when following me for our trip together but after we went separate ways home he ran into lots of problems with the Distronic cruise control. Here is the essence of a email he sent me after the trip that you might find informative:

"The cruise control cut out on us a total of 7 times in the last 2 1/2 weeks. I think I have it figured it out but Mercedes is not going to be able to fix the problem (most likely). Supposedly if the Distance Assist part of the Adaptive Cruise Control does not see a vehicle to slow down against, it will look for road signs like speed limit. If it also does not see a road sign it recognizes it will turn off after one hour.

Now just how much sense does that make??? Mercedes Birmingham Hoover has worked with Germany to define a laser aiming adjustment to allow the system to see a road sign better. Really what needs to happen is Germany needs to disable that one hour piece of code. I guess I shouldn't hold my breath on that one. When the cruise goes out it comes back very randomly after an hour or hour and a half or not at all for 3 days in one of our cases."
 

Mrshakedown

Active member
It’s happened a number of times on my 2019.

I’ve decided the dealers know nothing about these vans.

Whenever I mention any issue to them they say “hmm ive never heard that” so much so I think it’s their standard answer as to not own up to anything as I bet they know about all this crap and probably more.

They do say it like they are lying to your face oddly..
 

Boxster1971

2023 Sprinter 2500 144wb AWD
There is another thread related to this problem at this link:
Distronic cruise control acts weird | Page 2 | Sprinter-Source.com

This situation is disabling other safety systems like emergency braking. Time for US owners to file complaints with NHTSA to force Mercedes into changing this software design. Here is link for owners of newer Sprinters that have issues with Distronic system to file complaints.
Report a Vehicle Safety Problem, Equipment Issue | NHTSA

If enough people file complaints then NHTSA will ask Mercedes to respond and maybe this issue can be fixed.
 

coss370

Active member
Coss370,

Did you ever have it happen again? I had it happen multiple times (3500 2020 sprinter). Found my answer in a post by rprochnow on Winnebago owners forum. Caused by driving too long with no vehicle in front. Apparently no feedback from the radar sensor causes computer to think radar sensor malfunctioning. Only fixed by following another vehicle for a few miles.

Rprochnow post

I live in a low population area, so happened kind of often, including 2 hours after 3.5 hour drive to Mercedes dealer where they replaced the radar sensor.

crazy design!
But thanks to Rprochnow, at least I know what to do when it happens now.
his idea is to try turning off cruise control for a short time every hour or so if in low traffic. I haven’t had a chance to try that yet
Sorry for the late reply, don't check the forum often. It happened a few more times, but I would say the likely cause is dirty windshield and bad sun. The problem is that it doesn't just come back immediately after you clean it, causing little panics
 
Adaptive Cruise Control works from a gun in the lower grill. I'm not sure why people say the windshield may be dirty and that's why the Adaptive Cruise Control doesn't work.

Am I wrong?
.
.

MB Cruise Control Radar Gun Location.png
 
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2020LTU24MB

New member
We have had three such distronic cc failures and two had nothing to do with not following another vehicle. Those two were on longer time and distance sections of our trips. Any chance this “intermittent problem is connected to the corrosion problems in the EIS of 2019 & newer Sprinters?
 

2020LTU24MB

New member
A friend forwarded this to us. I’m surprised the MB shop we use didn’t mentions this. They seem to be up to date and very through. Guess they have to wait until the MB customer field testing generates enough info for them to publish service bulletin updates.

Battery....


Comments from LTV blog:


Anyone with a 2019 chassis have their "auxiliary battery malfunction"? It's happened twice now in our 2020 UMB. We were in Phoenix earlier in the month and the dealership replaced the auxiliary battery and we drove back home fine. We are now back in Calgary, Alberta and it happened again yesterday. My understanding is it allows for the operation of the electronic systems (like the electronic transmission shift) in the event of a main chassis battery failure. When malfunctioning it also stops the use of the cruise control and I'm sure a bunch of the other stuff I've not noticed. I need to take to my local dealer but wondering if anyone else ran into this? Part of the water issue? Phoenix dealer didn't offer any explanation other than they replaced the auxiliary battery and cleared the codes.


James Yuhn shared a link. November 1, 2019


Battery disconnect information for owners with the new 2019+ VS30 chassis Sprinter. The new Sprinter has the same disconnect near the throttle for the main battery as does the previous generation.


However, the new Sprinter also contains a small auxiliary battery. The aux battery provides backup power so that the transmission can be shifted to/from Park if the main battery dies. There is no mechanical linkage from the gearshift to the transmission, it is entirely electrical now.


The Sprinter owners manual not so helpfully states that when disconnecting the main battery for storage, the aux battery must also be disconnected. Pull fuse 32 from


the fuse panel on the side of the drivers seat. URL: https://www.upfitterportal.com/en-us/ Look under Technical Information and select Product Bulletins.


If you don’t disconnect the aux battery, it goes dead after a while. Don’t ask how I know this.


So to the point of my post. Mercedes has published on the upfitter portal a method to disconnect the aux battery without too much in the way of contortions. Simply remove fuse #32 from the fuse panel on the side of the drivers seat. It’s right there under the vinyl trim which LTV installed. Here is a link to the document on the MB site:


Homepage: https://www.upfitterportal.com/en-us/? fbclid=IwAR3RdeMNvAiQGeVlykxDTeWDPFADB58eyLC0cwRC19_g1PeK1Ti2BKzPSEU Under Technical Information select The Product Bulletins menu item and then scroll through the list to the Emergency Battery item.


Problem: Help! Just pulling LTV on 2019 chassis out of storage and have an ‘Auxiliary battery Malfunction’ as well as ‘Active Distance Assist Inoperative’. It’s been in storage (in Palm Springs) for a few weeks, with the Quick battery disconnect disconnected (by driver footwell) House bank batteries are 100% and operating fine. Anyone see either of these?


Answer: (James Yuhn) The small auxiliary battery has died while in storage and must be replaced. It is supposedly located under the drivers seat, though I’ve not personally laid eyes on it. You will have these error messages and no cruise control until it is replaced.


If you read the owners manual carefully regarding battery disconnect, it tells you to also disconnect the aux battery. But no information on where or how.




Battery....
Comments from LTV blog:
Anyone with a 2019 chassis have their "auxiliary battery malfunction"? It's happened twice now in our 2020 UMB. We were in Phoenix earlier in the month and the dealership replaced the auxiliary battery and we drove back home fine. We are now back in Calgary, Alberta and it happened again yesterday. My understanding is it allows for the operation of the electronic systems (like the electronic transmission shift) in the event of a main chassis battery failure. When malfunctioning it also stops the use of the cruise control and I'm sure a bunch of the other stuff I've not noticed. I need to take to my local dealer but wondering if anyone else ran into this? Part of the water issue? Phoenix dealer didn't offer any explanation other than they replaced the auxiliary battery and cleared the codes.
James Yuhn shared a link. November 1, 2019
Battery disconnect information for owners with the new 2019+ VS30 chassis Sprinter. The new Sprinter has the same disconnect near the throttle for the main battery as does the previous generation.
However, the new Sprinter also contains a small auxiliary battery. The aux battery provides backup power so that the transmission can be shifted to/from Park if the main battery dies. There is no mechanical linkage from the gearshift to the transmission, it is entirely electrical now.
The Sprinter owners manual not so helpfully states that when disconnecting the main battery for storage, the aux battery must also be disconnected. Pull fuse 32 from
the fuse panel on the side of the drivers seat. URL: https://www.upfitterportal.com/en-us/ Look under Technical Information and select Product Bulletins.
If you don’t disconnect the aux battery, it goes dead after a while. Don’t ask how I know this.
So to the point of my post. Mercedes has published on the upfitter portal a method to disconnect the aux battery without too much in the way of contortions. Simply remove fuse #32 from the fuse panel on the side of the drivers seat. It’s right there under the vinyl trim which LTV installed. Here is a link to the document on the MB site:
Daimler published a note on their upfitters portal in September regarding this issue. Pull fuse 32 from the fuse panel on the side of the drivers seat. URL: https://www.upfitterportal.com/en-us/ Look under Technical


Information and select Product Bulletins.


Don’t ask how I know all this. Dealer replaced mine under warranty. No out of pocket, but hassle of dropping off the MoHo for service.




Daimler published a note on their upfitters portal in September regarding this issue. Pull fuse 32 from the fuse panel on the side of the drivers seat. URL: https://www.upfitterportal.com/en-us/ Look under Technical
Information and select Product Bulletins.
Don’t ask how I know all this. Dealer replaced mine under warranty. No out of pocket, but hassle of dropping off the MoHo for service.

Homepage: https://www.upfitterportal.com/en-us/? fbclid=IwAR3RdeMNvAiQGeVlykxDTeWDPFADB58eyLC0cwRC19_g1PeK1Ti2BKzPSEU Under Technical Information select The Product Bulletins menu item and then scroll through the list to the Emergency Battery item.
Problem: Help! Just pulling LTV on 2019 chassis out of storage and have an ‘Auxiliary battery Malfunction’ as well as ‘Active Distance Assist Inoperative’. It’s been in storage (in Palm Springs) for a few weeks, with the Quick battery disconnect disconnected (by driver footwell) House bank batteries are 100% and operating fine. Anyone see either of these?
Answer: (James Yuhn) The small auxiliary battery has died while in storage and must be replaced. It is supposedly located under the drivers seat, though I’ve not personally laid eyes on it. You will have these error messages and no cruise control until it is replaced.
If you read the owners manual carefully regarding battery disconnect, it tells you to also disconnect the aux battery. But no information on where or how.
 
There was talk of this under-seat battery being replaced by a capacitor... can anyone confirm or deny this?

Which model year started getting the capacitor instead of the battery?
 

RVBarry

2023 AWD 170 DIY CamperVan
There was talk of this under-seat battery being replaced by a capacitor... can anyone confirm or deny this?

Which model year started getting the capacitor instead of the battery?
Hi, it's mentioned at
As of late build 2020/2021 vans the emergency park battery has been replaced with a capacitor.
I haven't seen any pictures of it.
 

Roamers

2020 4X4 170 Crew
More information on the "don't see a vehicle" timeout. 860 mile trip today. About 150 miles in, sensors cut out. There were many vehicles on the road with me so didn't think lack of vehicle sensing was the issue. Stopped for fuel, cleaned salt off everything, back on the road still no cruise.

Found "driver assist" page on dash monitor and pulled up behind a car to gauge speed. After a bit of time, cruise came active again. Kept driver assist display up and noticed that the sensors only know there is a vehicle present for ~300 feet ahead. I had been traveling speed limit before I lost cruise, so never had a car within sensing distance. Also noticed vehicles passing me were not pulling back in within the sensing zone to reset timeout. Remaining 700 miles drove 5 over speed limit, so periodically had vehicle in sensing zone and no more problems.

Also noticed that there is a green indicator next to the "cruise enabled" indicator that lites when a vehicle is in the sensing zone ahead of you.
 

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