2020 Buick Encore GX: sudden loss of power

Filed Sep 26, 2026 · Acceleration, Electrical · KS

While driving my 2020 Buick Encore GX, the vehicle experienced a sudden and dangerous loss of acceleration, immediately dropping into 'Reduced Engine power' limp mode in active traffic, but no other car was Infront or behind my car. A diagnostic scan revealed Diagnostic Trouble Code (DTC) P2138, which triggered the computer's safety override system to cut engine throttle. The official dealer repair invoice confirms a manufacturing and assembly defect covered under GM Technical Service Bulletin (TSB) #07-06-04-019G. The technician located water intrusion Panel/Body Harness Connector X112. The root cause was an improperly seated weather seal from the factory, which allowed moisture to short-circuit the accelerator pedal sensor voltage lines. The shop had to reposition the factory seal and apply dielectric grease to the terminals to correct the defect, for which I was charged out of pocket. This manufacturing defect caused a sudden, unpredictable loss of vehicle power on public roads, creating a severe rear-end collision hazard.

Filed Feb 17, 2026 · Engine, Transmission · TX

2020 Buick Encore GX; pulling out of a service station, my check engine light illuminated, and message on cluster stated: Engine Power Reduced. I loss throttle response for accelerating. Accelerator pedal was pushed to the floor and no acceleration. Vehicle entered limp mode. Drove 15 miles from service station to my home, in limp mode, unable to accelerate. Called a technician mechanic who check for Diagnostic Trouble Codes; DTC P0299 Turbocharge/Supercharge "A" Under boost condition; is Confirmed, Pending, and Permanent code. Loss of power to Power Train, unable to accelerate.

Filed Dec 16, 2024 · Acceleration, Engine · MN

My vehicle is undrivable. Multiple times per trip the check engine light comes on and I see multiple messages come on the driver information center. These are: Service ESC Reduced Power Service Adaptive Steering System The codes that come up are: P0089 for low fuel pressure P00C6 This results in an immediate speed reduction nearly causing multiple collisions with people following me on the highway. As a result I have been using a code reader to clear the codes so i can continue driving. I refuse to drive on busy highways so I am always forced to drive back roads. This needs to be figured out ASAP!

Filed Jun 22, 2023 · Engine · WA

I was driving on the interstate on June 7, 2023 heading to work doing the speed limit of 60 MPH and all of a sudden the check engine light came on and a message stated "Engine Power Reduced" and the engine literally dropped engine power immediately and thankfully there was nobody right behind me and I was able to get off the interstate to a safe place. I called the Buick GMC dealership where I purchased the vehicle and they said to bring it in. They pulled codes on it and it gave a code of "engine under boost" and they said they ran tests on it and could not find anything wrong after 3 days at the shop, they did a software update and told me to come and pick it up. Then not even a week later, I was driving and out of nowhere came the same engine light, message read "engine power reduced" and the engine lost power immediately and I called the Buick GMC dealership again and they said to bring it back in and it's there now. I called today to check in and they said they are going to test the Turbo on it and order parts, etc. but they still do not have a definitive answer as to what's wrong with it yet. I bought my 2020 Buick Encore GX new in November 2020 and it has about 26,000 miles on it. No recalls have been made on my VIN model - I am afraid to even drive this car again and get stuck somewhere away from help or at night - someone could have rear ended me when I lost power on the interstate doing 60 MPH and killed me!!!

Filed Jun 22, 2023 · Engine · WA

I was driving on the interstate on June 7, 2023 heading to work doing the speed limit of 60 MPH and all of a sudden the check engine light came on and a message stated "Engine Power Reduced" and the engine literally dropped engine power immediately and thankfully there was nobody right behind me and I was able to get off the interstate to a safe place. I called the Buick GMC dealership where I purchased the vehicle and they said to bring it in. They pulled codes on it and it gave a code of "engine under boost" and they said they ran tests on it and could not find anything wrong after 3 days at the shop, they did a software update and told me to come and pick it up. Then not even a week later, I was driving and out of nowhere came the same engine light, message read "engine power reduced" and the engine lost power immediately and I called the Buick GMC dealership again and they said to bring it back in and it's there now. I called today to check in and they said they are going to test the Turbo on it and order parts, etc. but they still do not have a definitive answer as to what's wrong with it yet. I bought my 2020 Buick Encore GX new in November 2020 and it has about 26,000 miles on it. No recalls have been made on my VIN model - I am afraid to even drive this car again and get stuck somewhere away from help or at night - someone could have rear ended me when I lost power on the interstate doing 60 MPH and killed me!!!