2021 Jeep Wrangler: start-stop system problems

Filed Jul 14, 2026 · Acceleration, Electrical · MN

While driving from [XXX] to [XXX], the vehicle experienced two sudden loss-of-propulsion events at highway speed. During the first incident in downtown [XXX], cruise control disengaged, the transmission abruptly downshifted, and the accelerator became largely unresponsive. The vehicle rapidly lost speed in traffic, and another vehicle nearly rear-ended me because I could not maintain speed or accelerate. The engine remained running, but the vehicle appeared to enter reduced-power or limp mode. I pulled over, shut the vehicle off, and restarted it. Normal throttle operation temporarily returned. The check-engine light and “Stop/Start Not Available” warning remained illuminated. After approximately three hours of otherwise normal driving, I activated cruise control again. The same condition immediately returned: cruise disengaged, the transmission downshifted, throttle response was lost, and the vehicle rapidly decelerated. Restarting again restored normal operation. This unexpected loss of propulsion created a serious collision risk because the vehicle abruptly slowed in moving highway traffic without allowing me to accelerate out of danger. The problem appears directly associated with cruise-control activation, although the exact mechanical or electronic cause is unknown. The vehicle has approximately 40,300 miles, was purchased as Jeep Certified Pre-Owned, and had a new OEM battery installed by an authorized Jeep dealership shortly after purchase. I am requesting that the federal safety agency investigate similar reports involving sudden throttle loss, abrupt downshifting, reduced-power operation, or loss of propulsion at highway speeds. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 2, 2023 · Electrical · MA

On 9/16 I went to leave for work for the day and my car would not start. The auto stop start system was illuminated with a warning. A neighbor jumstarted to car for me. I drove to my dealership where I was told both of my batteries had failed and I would need to replace them. I replaced both. Upon leaving the dealership my stop start was still showing a warning. I was told it would go off after driving for a few days. It did not. I returned to the dealership on 9/25 to see what was wrong. The code the vechicle was giving was low battery. I was told it was a software update and was sent on my way. This issue with my vechicle par of a RRT21-077 dated 6/24/21. I was never notified of this by Jeep. I was told when I brought this to their attention that because this probelem did not occur within 18 months of the bulletin my issue would not be covered. I am concerned that this issue will happen again and leave me stranded without power, as clearly it is an issue with this model.

Filed Feb 2, 2023 · Electrical, Engine · NJ

The vehicle's engine will randomly shut off and not turn back on. It has been to dealerships over 10 times for the same issue. They all attribute it to the start/stop battery, but it happens even when that feature is turned off. The vehicle's engine will shut off while driving and you cannot shift it into park. The only warning is a check engine light and "service auto start/stop system". There is no warning before the vehicle does it, and I have broken down in intersections, highways, and other dangerous locations. The vehicle duplicated the issue on the dealers lot, but they claim " no codes, no repair".

Filed Oct 17, 2022 · Acceleration, Engine · DC

The incident occurred when I attempted to shift the transfer case into 4-Low. The sequence of events is as follows: 1. I stopped the vehicle and shifted into Park. 2. With my foot on the brake, I shifted into neutral and attempted to move the transfer case lever from 4-High, to 4-Low. 3. As I started to move the transfer case lever, a warning appeared in the instrument cluster stating, "Vehicle speed too high to shift". 4. Auto-Park engaged 5. The engine, uncommanded, with my foot still on the brake, began to increase in revs slowly. 6. Check engine light illuminated, the engine continues to increase in revs. 7. When the engine reached 6-7k RPM, I hit the engine start/stop button and held it down until the engine turned off. The engine was still climbing in revs until this point. 8. I restarted the engine and could shift into 4-Low successfully. "Off-road cruise control disabled" warning light illuminated and remained on until I shifted back into 4-High. Check engine light remains on after multiple starts.

Filed Jun 20, 2021 · Acceleration, Electrical · ID

While driving on a one way high way. Was about to overtake a semi truck. While half way on the opposite lane doing a legal overtake my acceleration decreased significantly, nearly causing my passengers and I to get into a head on collision with the another vehicle. All of this was due to the fact that the Jeep’s acceleration was decreased. The following warning appeared and code was registered: Check engine light code P00AF Service Electric Throttle Control stop/start unavailable Service stop start system Acceleration issues after shutting down my engine all the codes disappear and vehicle precedes to normal driving. I am extremely worried that this might happen again and pace me and my loved ones in a dangerous situation as well as other people on the road