2016 Chevrolet Impala Limited electrical system problems

“When I put the car in park and try to turn the car off the Shift Park message comes on preventing me from cutting the car completely off. I put in back in drive or reverse then back in park it still dings and shows the message. I takes a number of repeating these steps for it to stop and turn off and this is happening every time I'm trying to turn the car off.”

“I am filing a complaint regarding ongoing and worsening issues with my Chevrolet vehicle, which appear to point to broader defects involving the engine and electrical systems. Months ago, while driving, the car suddenly lost power and displayed "Engine Power Reduced." I had to keep using it due to work needs. Over time, it hesitated more during acceleration and felt increasingly unsafe. When I finally brought it to a Chevrolet service center, I was told the issue involved the pistons. The vehicle also regularly shows a "Shift to Park" warning even when the gear is in Park, raising concerns about the transmission's reliability. The power loss continues, especially when going uphill — again triggering the "Engine Power Reduced" alert and dropping the speed to no more than 35 MPH. A diagnostic showed a P0302 code for a cylinder 2 misfire. The radio head unit, already replaced once under warranty, failed again after just 9 months. Prior to the worsening idle and gear issues, I also received network-related codes involving the ECM and transmission computers. Although I’ve replaced the alternator, the car still shows "Service Electric System" warnings, suggesting…”

“Took my car to Chevy dealership to diagnose my car, as it was rough idling, causing hesitation, and knocking... all while the check engine light was on. They showed me two codes my car was giving from the check engine light. They said he would look further into it. They told me I needed a tune up, though I had gotten a tune up 4 months prior. They fixed some things and charged me over $4,000. The day I drove off the lot, the problems were still present. On my way home going about 50 mph, my car slowed down and the engine reduced power illuminated. I kept driving because I needed a car for work. The car continued to decline and acted like it didn't want to accelerate when pressing the gas. I finally took it back into chevy, and they told me it was my pistons. I'm 90% sure there is a defect that they won't tell me about, or the won't fix. I've had the car 2 years. Now the car won't run.”

“To whom it may concern, I am writing to formally report a recurring safety-related issue with my 2016 Chevrolet Malibu. The vehicle consistently displays a “Shift to Park” warning message, even when the gear selector is properly in the Park position. This malfunction prevents the car from turning off completely and poses a serious safety and reliability concern. This issue first occurred while the vehicle was under warranty, and the dealership performed a repair. However, the problem has returned, and my warranty has since expired. Despite the previous fix, the issue continues to persist. This malfunction is widely documented among other 2016–2019 Chevy Malibu owners and appears to stem from a design or manufacturing flaw in the shifter assembly or park switch. I am concerned that this defect could: Prevent the vehicle from being securely parked. Lead to battery drain due to the vehicle not shutting off. Pose a risk if the driver believes the car is in park when it is not. I am requesting that Chevrolet consider this a safety defect and either recall the affected vehicles or offer extended coverage for repairs. I also ask that NHTSA investigate this issue…”

“Vehicle will display on dashboard “Shift to park” while the vehicle is placed in “P”. The engine will turn off, but the power remains on until the battery is disconnected from the vehicle. Codes have been verified by the Chevrolet dealership.”

“I had my vehicle for about 2 years. I noticed that after I went over a certain amount of mileage, my car went into an engine power reduce mode. With the engine power reduce mode my vehicle could only go 25 mph. This was happening to me when I was driving on major highways, etc.. I would have to pull over and stop the vehicle because after certain amount of time it also would tell me oil pressure low to stop engine. I took it to the Chevy dealership to have it looked at. I got the runaround with trying to figure out exactly what the issue was. They kept telling me that it was something else I spent over $1600 in repairs due to them, telling me that they found the issue and corrected it. After about another week or two, The same issue happened, engine power reduced stop engine oil pressure low. The most dangerous part about it is again I’m driving on interstates heading to work, etc. and the car is slows down on the interstate not allowing me to go over 25 mph again having to pull over on the interstate to give the car a break, crank it back up and get to a safe location. After having multiple mechanics look at it, still unable to fix. It started to get worse…”