2020 Jeep Grand Cherokee: start-stop system problems

Filed Oct 16, 2026 · Electrical · IA

This concerns the Auto Start Stop (ASS) battery installed at the factory that has the vent hole in the wrong place and was improperly installed so that the vent tube could be dislodged and allow hydrogen gas from charging into the cabin. Both the main battery and ASS battery are installed under the passenger seat and vent outside through a hose. I discovered this situation while replacing the main battery. I contacted Stellantis via email (with and explanation of the numbers in the photo) and they were not willing to address the issue. I have attached a copy of the email and also a photo of the battery compartment. Also, the new ASS battery has the vent hole in a new location. It is my opinion that this is a safety issue.

Filed Mar 7, 2026 · Electrical, Engine · PA

on or around 12/15/2024 (42257 miles on vehicle) jeep will power on start and stop, all alights on dashboard light, unable to shift into or out of gear when parked. When driving but stopped at a red light car shut off. Attempted to restart unable to, car put into park attempted to restart lights came on but engine didn't turn over. Tried again few minutes laster and the car turned on. Returned apartment, parked car. was unable to shift car into park, car shut off on its own again, car then able to go into park. A few days later start engine, car turns on put car in reverse, car shut off on its own, all lights and warnings on dashboard light up and stay on. Unable to start engine, unable to shift car into park. turn car off, shift into park, on 12/17/24 Car towed to Lake Chrysler dodge jeep ram auto Lewistown PA. told that it was the can bus connector needed to be replaced. Part replaced. 10/10/25 (54630 miles) car in for inspection, oil change, reported to mechanic engine was making high pitched sound/noise when driving up steep hill on highway the week prior. Was told by mechanic "that is normal when driving up steep hills, after a long drive" " we didn't hear it or find anything" Car continued to make this noise on the same hill since. Car in for oil change at David Dodge on 1/12/26 (58,974 miles) reported to mechanic again that engine continues to make a high pitched sound/noise when going up hills, on highway drives and after longer drives. per shop nothing was found. Asked if I should make an appointment for it to be tested and told no not needed. On 3/2/26 check engine light on, waring start/stop unavailable service stop/start system this happened off and on for next few days. Car brought to mechanic on 3/6/26 (60,000 miles) diagnosic test run cylinder misfire, R and R intake manifold to check coil and spark coolant found on spark plug, borescope #3 cylinder Head gasket, cylinder head, block issue . Recommend total engine and radiator replacements

Filed Jul 21, 2025 · Transmission · UT

At approximately 54,000 miles the transmission is not shifting. I parked in a parking spot, go into a store. Then come out and the vehicle will not shift into park or reverse. The check engine light came on for the park by wire issue. These transmissions have been known to have rough shifting and my vehicle has been no exception. It’s shifted rough at low speeds and the eco mode and auto start/stop system have also made it feel less than smooth to drive.

Filed Sep 6, 2024 · Driver assistance, Electrical · CA

I am reporting significant safety issues with my 2020 Jeep Grand Cherokee Limited X. The vehicle has repeatedly experienced failures in critical safety systems such as Adaptive Cruise Control (ACC), ParkSense, and Lane Departure, which randomly disable while driving, particularly in cold weather or after a restart. These failures compromise essential safety functions necessary for highway driving and parking. Additionally, I encountered a severe issue regarding the vehicle’s lack of over-voltage protection. While charging the battery, it was accidentally exposed to 48 volts instead of 12 volts, resulting in damage to key electronic modules, including those controlling safety systems. This lack of protection from foreseeable charging errors is concerning, especially given the advanced electronics in modern vehicles. Other Jeep owners have reported similar issues related to voltage fluctuations affecting ACC, Lane Departure, and ParkSense systems. Battery-related issues seem to be directly linked to the failure of these critical safety features​(Jeep Cherokee Club)​(Jeep Forum). Voltage instability, particularly with the Engine Stop/Start (ESS) system, has also been widely discussed, further pointing to potential flaws in Jeep’s electrical design. Given the critical nature of these systems, their failures due to inadequate over-voltage protection and inconsistent electrical performance represent a serious safety risk. I request that the federal safety agency investigate these concerns, as they may be affecting a broader range of Jeep vehicles, putting drivers and passengers at risk. While a fire did not occur, the potential is there due to the burning of electronics with strong odors and smoke.

Filed Mar 19, 2023 · Electrical, Engine · MI

1.The electrical/engine/powertrain systems failed 3 times. The vehicle is available for inspection. 2.As the problem progressed, the car would only go forward, no ability to go in reverse, or to be put in park. 3.The dealership replaced the ABS Module, then later the Engine Control Module. 4.Event 1: September 1, 2022 Warning light for the stop/start feature came on, also the ABS light and check engine light. Dealership kept the car for the day, did a diagnosis, returned the vehicle stating it was safe to drive, and that an ABS Module had been ordered. Would contact me to schedule the repair. Event 2: September 8, 2022 Dashboard lit up like a Christmas tree, all warning lights came on, as well as all lights on the gearshift panel/center console, which kept blinking. Car would only go forward. Dealership installed ABS Module and returned the car to me. Event 3: September 29,2022 Warning light for the stop/start feature and check engine light came on again. I took the car to my local dealership with major concerns that the previous repair was not the only problem occurring and left it there. The Engine Control Module was eventually replaced. 5. I had no use of my Jeep Grand Cherokee from September 29 until November 8, 2022. 6. I have a major concern about the safety of this vehicle.

Filed Oct 23, 2022 · Engine · CT

The vehicle when drive shuts engine off and tell you to shift to park. It has don’t it to me a few time and twice I almost got rear ended. I took it to the dealer and they say they can’t find anything wrong with it. To shut off the stop start system but it still does it when I stop start system is off. If you go online a lot of people are having the same issue Jeep just doesn’t want to acknowledge it. This is very dangerous because it does it at any speed stop and go or you could do 65 on the highway and it does it in jeep is aware of this because many people have complained about it and it’s going on death years. After some time, the system completely shut off and I was able to drive it without the stop start system. The message that came out was stop start system needs servicing, but the jeep dealer has no idea what that is. They have tested the battery and they said it’s OK. It Hass to do something on the transmission or something yeah true but this is going to be something if they don’t fix someone’s gonna get hurt and when they get a lawsuit that’s what you’re gonna do something for the negligence.