2021 Ram 1500: start-stop system problems

Filed Feb 16, 2026 · Engine · WI

MGU unit failure. Truck is less than 5 years old and just hit 60k miles. Noise came on very abruptly and was lucky enough to get it to a dealer nearby where I was traveling. Still was stranded 4 hours from home and needed a rental to get home. I got a battery warning light and auto start/stop malfunction light and 20 minutes later the truck was dead. I have a family of 5 and need a vehicle for work and to transport kids to school/daycare. Technician said it could take upwards of 8 months to get the replacement part. This is absolutely ludacris for something like this to happen and potentially causing financial damages to people. Dealer offered $10k less than the truck is worth because of the issue so I can’t even get a fair trade in value if I wanted to trade it in. Ridiculous!

Filed Jun 30, 2025 · Electrical · ID

The MGU of the 2021 Ram Laramie (e-torque) is not functioning properly and hampers the safety of the vehicle. The MGU, which controls the alternator, will not charge the battery beyond 13.0/13.2 volts during driving. As a result, when sitting for several days, the battery will not have sufficient voltage to start the vehicle since it is not charged fully during driving. Additionally, the MGU is now making a strange bearing noise so we will see if a failure is imminent. Considering this MGU controls the starting of the vehicle during stop/start, and the battery is not charging sufficiently to ensure the owner is not stranded, I consider this a significant safety issue (especially when I live in a place with winter of 8 months). I have not seen any warning lamps, but the charging indicator/screen shows 13.0 as below normal.

Filed Dec 22, 2023 · Engine · TX

While driving (10-18mph), engine suddenly stalls (going from Run into ACC mode on the engine start/stop) and notifies me via dash warning that the vehicle must be put into park and continues to coast forward as if in neutral. I was able to pull over to the side of the road and turn the dial from drive into Park. After a few seconds, I press the engine start/stop button and the engine restarts and i turned the dial to Drive. This may be a problem with the eTorque.

Filed Apr 27, 2022 · Engine · IA

Slowed down on residential street to make a right turn and after turn was completed the engine was off. There were no warning lights or chimes and engine stall was so smooth I didn't know it had happened. Auto start/stop was already disengaged as I do this every time I start the vehicle. Center cluster told me to shift to part and that auto braking (parking brake) had been engaged. The engine did restart as normal and was able to drive. All other accessories functioned as normal throughout the whole incident.

Filed Apr 7, 2022 · Electrical, Engine · CA

The start/stop system will turn frequently display an error stating the "auto start/stop system in not available" When coming to a traffic stop, the engine will turn off and will not restart for 2-3 minutes while sitting in traffic

Filed Mar 5, 2022 · Engine · FL

Purchased this brand new truck back in July, 2021. As of today, it only has 7,200 miles on it. It has been hesitant when I press on the gas, as if it is going to stall out. I just figured it was because of the auto start/stop feature so I usually try to remember to disengage it. Then it shut off completely on me two different times this past week while I was making a right hand turn. When the engine shut off, the emergency brake engaged. I brought it to the dealer where I purchased the vehicle and they said no codes came up. They also test drove it and found no issues. I am very concerned for my safety and need this problem looked into. I belong to a Ram forum and it seems like many, many people are experiencing the same issues.

Filed Feb 7, 2022 · Acceleration, Electrical · FL

I almost died, when my truck stalled as I was entering a major thoroughfare. This primarily has to do with the auto start/stop option on my Ram, which if you do not come to a complete stop, and attempt to accelerate with this feature on, the vehicle stalls. This has happened to me several times, and if you go on the online forums it is happening to many other Ram drivers, it is a serious safety issue, as you have no control over the stall due to the computer. Basically, when I am coming to a stop and then accelerate with the vehicle at a slow crawl, 2-3 MHP, the truck stalls. Imagine rolling through a yield sign and your vehicle stalling, with oncoming traffic headed your way, serious safety issue. Extremely lucky to not have been involved in a crash with oncoming traffic headed my way going 55 MPH, I was able to stay in the yield lane.

Filed Jan 4, 2022 · TX

2021 Ram 1500 Laramie crew cab with the Hemi etorque has 10k miles. Today traveling at approximately 35 mph I slowed to yield at a round about but did not reach a complete stop, as I went to go my truck went forward into a very busy round about and the engine shut off completely. I stalled, rolling into a 2 lane roundabout on a busy road, fearful for my life. Center screen stated to place vehicle in park before starting. I placed my flashers on and mid panic attack managed to think enough to restart the engine. I placed the shifter dial into Park and restarted without any issue. The emergency brake had become engaged at this time. I was able to release that and safely exit the roundabout. I did cause a backup and was left in a potentially lethal situation. Very very scary. No issues after this. Had my husband check truck when I got home, no error codes detected. I do not know if it is related but I do on occasion feel like there is issue with the auto start/stop feature “sticking or hiccuping” when I do not come to a complete stop (our area had many round abouts)