Ram Promaster adaptive cruise problems

Filed May 24, 2026 · Electrical, Steering · NC

The vehicle's power steering does not work properly, especially at slow speeds and when attempting to back up. However, it has also failed while traveling on the interstate highway at high speeds. When you attempt to make a turn, the power steering feels like it is fighting you and wants to pull the vehicle back in the opposite direction. I took the vehicle in to be serviced, and they replaced the battery which removed previous warning messages. On two occasions, while traveling at slow speeds and making a turn into a shopping center parking lot, the vehicle resisted my attempt to make the turn such that had a car been coming out of the parking lot, rather than complete the turn, I would have run directly into the side of the other vehicle. While travelling on the interstate at 70 mph, I momentarily lost steering and had there been vehicles behind or beside me at the time, I believe it would have resulted in an accident. Fortunately, the cruise control simultaneously shut off.

Filed May 7, 2026 · Driver assistance · WA

Adaptive Cruise Control (ACC) randomly quits working, produces a yellow warning light and digital message saying it has failed and service required. This failure happens at completely random times and last for hours to days and then randomly starts working again. This began happening after purchase in 2024 and was first sent into the dealership for repair in May 2024. The problem persisted with additional dealership visits in: June 2024, Sept. 2024, Jan. 2025, May 2025, Sept. 2025, Oct. 2025, Jan. 2026. Now my warranty is expired and dealership is refusing to work on the vehicle. Stellantis eventually put out TSB 08-065-25 which was completed Oct. 2025 and it did not fix the problem. All repairs have been software and radar alignment related, no hardware for parts replaced. My vehicle is available for inspection. My safety has been put at great risk in at least two different ways: first it randomly stops working which leaves the vehicle no longer being controlled, second, I have an expectation of additional security from purchased equipment specifically following distance and lane management. I lose this additional layer of safety for hours or days when the system fails. The problem has not been reproduced but has been confirmed via OBD2 reader. Vehicle has been to 7 documented Stelantis dealerships.

Filed May 7, 2026 · Driver assistance · WA

Adaptive Cruise Control (ACC) randomly quits working, produces a yellow warning light and digital message saying it has failed and service required. This failure happens at completely random times and last for hours to days and then randomly starts working again. This began happening after purchase in 2024 and was first sent into the dealership for repair in May 2024. The problem persisted with additional dealership visits in: June 2024, Sept. 2024, Jan. 2025, May 2025, Sept. 2025, Oct. 2025, Jan. 2026. Now my warranty is expired and dealership is refusing to work on the vehicle. Stellantis eventually put out TSB 08-065-25 which was completed Oct. 2025 and it did not fix the problem. All repairs have been software and radar alignment related, no hardware for parts replaced. My vehicle is available for inspection. My safety has been put at great risk in at least two different ways: first it randomly stops working which leaves the vehicle no longer being controlled, second, I have an expectation of additional security from purchased equipment specifically following distance and lane management. I lose this additional layer of safety for hours or days when the system fails. The problem has not been reproduced but has been confirmed via OBD2 reader. Vehicle has been to 7 documented Stelantis dealerships.

Filed Sep 26, 2024 · Acceleration, Driver assistance · TX

While cruising at highway speed with adaptive cruise control enabled, the vehicle will incorrectly detect traffic/speed signs and will rapidly decelerate on a highway in traffic. I believe that the message that displays after detecting the new speed limit (improperly based on a sign other than a highway speed limit sign) without giving the option to reject using the "resume" button before. There is an option to disable traffic/speed sign detection, but that must be manually disabled in software every time the vehicle is re-started. Adjustment of the speed during adaptive cruise control based on traffic/speed signs should be disabled for safety. It's fine to have the speed limit displayed on the dash, but dangerous to have the vehicle adjust speed on its own without sufficient warning, or at all. I would like to request that RAM be directed to disable the software connection between traffic/speed sign detection and the adaptive cruise control so that, just like regular cruise control, the operator chooses the vehicle's speed. Note that this issue has happened many times since I've owned the vehicle, which was purchased as new, but I am now complaining to the federal safety agency because I experienced multiple incidents on my most recent trip that might have risked a rear-end collision from a vehicle following me when deceleration occurred.

Filed Sep 19, 2023 · Acceleration, Driver assistance · CA

When driving on a freeway or highway, without cruise control on, & the pavement surface changes color &/or texture (eg: going onto a bridge/overpass) the vehicle will decelerate quickly & without us pressing the brakes. All the systems were checked by Dodge Ram & were showing no errors with software etc, as we thought this was traction control not working properly due to a software problem etc.

Filed Aug 17, 2023 · Brakes, Driver assistance · MO

The left brake actuator (68603568AA) literally fell apart on the vehicle at 40,000 miles. This triggered a warning on the dash and disabled emergency braking as well as cruise control. The local RAM dealers refuse to do anything about it because the warranty expired 4,000 miles ago, so we took it to an independent mechanic. They ordered the replacement part but informed us it was back ordered with no ETA and that there are no aftermarket parts available. After an exhaustive search, the mechanic was able to secure the factory part, only to find out the right actuator (68591375AA) was in a box labeled for the left side. I personally spent several days looking for another. I even called dealerships in Canada and was told it’s on a “continent-wide backorder with no ETA." Finally, we were able to secure another, only to discover the exact same problem upon arrival. Now, the mechanic has been trying to order a right-hand actuator in the hope the left one might be in the wrong box as well and a THIRD left. The vehicle has been completely inoperable for over two months, with no end in sight. This vehicle is critical to our business and we've had to rent a replacement at over $500 a week. So far, this has cost now us over $3,000...for what should have been a $200 part and an hour of shop labor. I strongly believe Stellantis should be covering all of this for us, as they are the ones responsible for the complete lack of parts availability for critical safety parts such as emergency brakes and considering how close the problem was to the warranty expiration.

Filed Dec 3, 2022 · Acceleration, Driver assistance · FL

When using Adaptive Cruise Control (ACC) with Traffic Sigh Assist (TSA) engaged (the default) on an interstate or other high speed road - for example the current highway speed limit is 65 and the ACC maximum speed is also set at 65 MPH, the TSA (wrongly) detects a much lower speed limit, say 25 MPH, the system flashes a warning AND AUTOMATICALLY APPLIES THE BRAKES without allowing the driver to respond to the warning message. According to the user manual, what is supposed to happen, is that the TSA warning message displayed on the dash says "new speed limit detected" and SUGGESTS that the driver can accept the detected speed limit as the new ACC maximum speed by pressing the RES resume button on the the steering wheel. If the driver does not respond, the ACC max speed stays as set. This is seriously dangerous! imagine going 65 MPH in heavy traffic and suddenly, unexpectedly the brakes are applied so violently that the vehicle skids and swerves out of its lane. This has happened multiple times to me. I believe this is caused by 2 problems: 1 The TSA wrongly detects a significantly lower speed limit sign. I don't know for sure but I guess it might "see" a sign on an exit ramp or parallel service road. 2 The vehicle automatically sets the new TSA speed as the ACC top speed and automatically applies the bakes instead of allowing the driver the option of setting the new speed limit by pressing the RES button. I have spent the last week trying to report this to the RAM dealer and Customer Care but they don't seem to be very responsive. They say I should schedule and pay for a diagnostic session but they have no openings until mid-January. Even if I took it in, I doubt the diagnostics would show anything because this is most likely a software issue. It would also be difficult to duplicate on local roads. I do know another person who has reported this same problem on YouTube and is able to recreate it as detecting a speed limit sign on a parallel service road.

Filed Nov 13, 2022 · Acceleration · NH

The text coincides with this video I made. Here is its URL. https://youtu.be/hpA-Dw_-ihY This is my second time reporting this issue. My first report was comprised of just text. I was told that a video would be more helpful. The issue follows: Periodically when I have been using Adaptive Cruise Control the van will automatically, harshly apply the brakes in the middle of the highway. It took me a while to figure out what was happening. It has to do with Traffic Sign Assist which is enabled by default. When the van detects a speed limit sign that is at a speed limit slower than what I am traveling, a message appears on the dash that says "New Speed Limit Detected. Press "Res" to Reject" This is the opposite of the way the owners manual says Traffic Sign Assist should work. The owner's manual says when a new speed limit is detect the user will be given the OPTION to accept the new speed. The manual says, if the user does not accept the new speed the vehicle will continue as it was. It will not apply the brakes. The consequence of the way it is implemented in my van is that if you do not see the message (because your eyes on the road) the van will AUTOMATICALLY apply the brakes. I have had it happen when traveling 65 mph and encountered a 25 mph speed limit sign at an exit. It only occurs with white speed limit signs. A 45 MPH speed limit sign appears on a service road at time :16. Just as the speed limit passes out of my FOV the message appears on the dash and the brakes are applied when I do not press "Res" to reject the new speed limit sign. Each of the times it happened in this video, first when it encountered a 45 mph sign and later when it detected a 55 mph, I was not expecting it. If you zoom into the video, or the attached picture, you can see the message.

Filed Nov 13, 2022 · Driver assistance · TX

While using adaptive cruise control and traffic sign assist, the vehicle has a feature called intelligent speed assist. It is supposed to detect new speed limits signs and ask the user if they want to adjust their set speed. Instead, the feature automatically changes the set speed without user input. For example, you are going down the highway with adaptive cruise control set to 75 mph. The vehicle erroneously picks up a lower speed limit of 45 mph (could be for feeder road, highway exit speed, or old construction sign, etc...). Within a few seconds the vehicle begins to aggressively brake on the highway in order to reach the lower speed limit. This is very dangerous as it is a surprise to the driver and could result in a collision.

Filed Nov 4, 2022 · Acceleration, Driver assistance · NH

Is intelligent speed assist implemented backward in the new Ram Promaster 3500? I attached a screenshot of the owners manual page describing how it should be working. I have experience several instances of the van automatically slamming on the brakes when traveling down the highway when the van recognizes a 25 mph speed limit sign for an off ramp. I have not been the only one. There are other posts about similar situations on the Ram Promaster Facebook page. I have a 2023 Solis 59PX that is built on the (new) 2022 Ram 3500 chassis. My Promaster happened to come with adaptive cruise control. This post is regarding the implementation of the intelligent speed assist feature which can automatically adjust the max speed of the van based on traffic signs it recognizes. The manual says that "the message in the instrument cluster display will indicate the new detected speed limit by suggesting the driver to press "RES" to accept it." Where the manual says the instrument panel prompts the user to press a button to accept the suggested speed, I recall my instrument panel requiring me to press a button to dismiss the accepted speed. If I didn't see the prompt to dismiss the new speed, I recall the van automatically changing speeds. I recall mine switching speed on several occasions, automatically, without having to press anything, which resulted in some dangerous moments when traveling 65 MPH on the highway and the van detecting a 25 MPH sign for an off-ramp and slamming on the brakes. I am wondering if it is implemented backward in my van. I recall it saying "dismiss" where the manual says it should say "accept". The manual describes the system working in a way that makes more sense to me and is opposite of the way I recall mine working. In the manual it describes the system making a suggestion to change based on the sign but requires user input to actually accept it. There are several posts about the same thing on the RamPromaster Facebook page.