2018 Chevrolet Volt power train problems

“FAILURE SUMMARY & SAFETY RISK: While operating in live traffic, the vehicle experienced a sudden loss of motive power and entered a "Propulsion Power Reduced" failsafe mode, creating a severe rear-end collision hazard. The vehicle is currently grounded and remains available for inspection upon request. WARNING SYMPTOMS & DIAGNOSTIC CODES: The instrument cluster illuminated the Malfunction Indicator Lamp (Check Engine), the ABS warning indicator, and displayed a persistent "Propulsion Power Is Reduced" message. A diagnostic trouble scan confirmed active high-voltage communication failures and powertrain faults: U2603 (Lost Communication with Hybrid/EV Battery Interface Control Module), P25A2 (Brake System Control Module Requested MIL), and ABS code C0500-00. PRIOR HISTORY & FAILURE TO CURE: This identical high-voltage Battery Energy Control Module (BECM) failure previously occurred in December 2025 at 97,808 miles and was presented to an authorized Chevrolet dealership for repair. The facility claimed the vehicle was repaired, but the exact same catastrophic high-voltage failure recurred in under 4,000 miles (at 101,635 miles). MANUFACTURER POLICY & OBSTRUCTION…”

“The vehicle frequently fails to register that the transmission has been shifted into Park. When this happens the instrument cluster displays "Action Required / Shift to Park" and the power (STOP/START) button will not shut the vehicle off. The condition is intermittent. I can usually clear it only by shifting through the gear positions and back into Park repeatedly, sometimes many times, before the vehicle will power down. SAFETY RISK: Because the transmission control module does not confirm Park, I have no assurance the parking pawl is engaged when I leave the vehicle, creating a rollaway hazard. The vehicle also cannot be shut down, which leaves its systems energized and drains the 12-volt battery, risking being stranded. I now apply the parking brake at every stop as a precaution. WARNING MESSAGE: The "Action Required / Shift to Park" message first appeared within days of purchase. I bought the vehicle used on 07/29/2026 at 69,471 miles and reported the fault to the selling dealer on 08/10/2026, twelve days later. CONFIRMED BY DEALER: Yes. On 08/19/2026 the selling dealer's service center diagnosed the cause as "internal shifter microswitch failure" and…”

“What component or system failed? When the BCEM failed on my car, it led directly to the transmission failing as well as the PIM. I was driving normally then had a completely inoperable car with no warning. I was told to pay over $17k for repairs by the dealership because there is no recall on the transmission, but I see proof that this is a common issue among Volt users. There needs to be a recall and repair to keep the road safe. How was your safety or the safety of others put at risk? I was driving on a busy road to school when my car fully locked up, jerked like crazy, and became inoperable. If I had been somewhere like a freeway instead of in front of a school, I likely would have become badly injured when the wheels stopped even turning. The tow truck even had to use wood under my wheels to get it onto the tow truck. Has the problem been reproduced or confirmed by a dealer or independent service center? I took it to the dealership and worked only with them. They replaced the BCEM without charge but have left me with an inoperable vehicle because I am unwilling to pay twice the cost of the car to repair it. Has the vehicle or component been inspected by the…”

“I was driving my 2018 Chevy Volt at about 30 mph on EV mode. The battery was at 50%, the car was performing normally. Then the battery jumped to 100%, the check engine light came on, and the vehicle lost power. I was in rush hour traffic and unable to get the vehicle to go faster than 5-10 mph. I switched to "normal" mode to engage the gasoline engine, hoping this would help but it did not. The gas engine RPM fluctuated wildly and did not restore the ability to accelerate the vehicle. I was still unable to go faster than 5-10 mph. I was a few blocks from home and managed to get home safely. The engine code was P1E00. I put the vehicle on the charger and it seemed fine the next day. This exact situation I ran into - reduced engine power - is addressed in Special Coverage N232432680, which includes this vehicles VIN. I took the car to the GM dealer today and they are telling me that the car is fine, they can find no problems. I mentioned that this issue is covered under Special Coverage N232432680, and was told that unless they can reproduce the issue in the shop, that they cannot apply Special Coverage N232432680.”

“The vehicle (2018 Chevrolet Volt) is experiencing an intermittent failure of the Battery Energy Control Module (BECM). Diagnostic trouble code P1E5B was stored in the system. This is a well-documented defect in this vehicle population that frequently results in a sudden, unexpected loss of propulsion power while driving ("Propulsion Power Reduced" mode), posing a significant safety risk in high-speed traffic. ​Although a Chevrolet dealership confirmed the presence of the stored fault code, they refused to perform the repair under the extended warranty (Special Coverage N23243268) because the Check Engine Light was not actively illuminated at the exact time of inspection. The manufacturer requires the vehicle to be operated until the fault recurs, exposing the driver and others to the danger of stalling on highways or at busy intersections. The failed component remains in the vehicle and is available for inspection.”

“My 2018 Chevrolet Volt frequently fails to recognize when the vehicle is shifted into Park. The dashboard displays “Shift to Park” even though the gear selector is already in Park. When this occurs, the vehicle will not power off, requiring multiple attempts to move the shifter before shutdown is possible. This creates a safety risk because the vehicle may be left powered on unintentionally and may not properly secure itself in Park. In one occasion, the vehicle moved backwards even when shifter was in Park, which created a collision risk. This is a known defect affecting many GM vehicles, including the Chevrolet Volt, and has been widely reported by owners. I am concerned about unintended vehicle movement, battery drain, and driver safety.”