2018 Chevrolet Volt transmission problems

Filed Sep 25, 2026 · Electrical, Fuel system · OH

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 OF REPAIR: General Motors recognized this hazardous defect under Special Coverage N232432680 (covering BECM replacement for 15 years/150,000 miles at $0.00 cost). This policy links to GM Master Bulletin 07-00-89-037S mandating direct-bill Courtesy Transportation for grounded safety defects. Despite this, when presented for warranty repair, the authorized Chevrolet dealership explicitly refused intake and refused to honor the transportation mandate, stating on the record: "Yes, I do decline". GM Corporate (Case 98734634) admitted coverage applied but failed to compel franchise compliance, leaving a dangerous, immobilized high-voltage hybrid vehicle stranded without access to safety-mandated repair bays.

Filed Aug 27, 2026 · Electrical, Transmission · TX

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 recorded the correction as "Replaced Transmission shifter controller assembly and cleared codes" (repair order 1133072). The fault returned within approximately half a day. On 08/26/2026 the dealer opened a second order for the same concern, recording the same cause and the same correction and listing the same part, shifter assembly part number 13540961 (invoice 1133224). The vehicle is currently at that service center and the defect is not corrected. The condition is worsening — it occurs more often and takes more attempts to clear than when first reported. The vehicle is available for inspection. It has not been inspected by the manufacturer, by police, or by an insurance representative.

Filed Aug 7, 2026 · Transmission · CA

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 manufacturer? Dealership. But also, as mentioned, this is clearly common and needs to be recalled. A 2018 car with 117k miles of gentle driving on a well maintained vehicle shouldn't be failing, and there shouldn't be so many Volts being sold for parts because their transmission failed. This is clearly a dangerous issue related to production and should have a recall. Were there any symptoms of the problem prior to the failure, and when did they first appear? I bought the car with just under 16k miles in 2021 and within 3 months I had symptoms, but the dealership couldn't figure them out, as they happened intermittently and only in heat, and the dealership always sent me away without repairs. The failure itself happened at 62°, but was foreshadowed by lesser versions of its demise.

Filed May 1, 2026 · Acceleration, Fuel system · NC

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.

Filed Apr 29, 2026 · Electrical, Transmission · PA

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.

Filed Dec 22, 2025 · Transmission · WA

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.

Filed Dec 9, 2025 · Electrical, Fuel system · CO

On June 27, 2025, while driving, the vehicle displayed a "Propulsion Power Reduced" warning message and a Check Engine Light illuminated. I immediately experienced a loss of power. I brought the vehicle to an authorized Chevrolet dealer the same day. On July 1, 2025, the dealer diagnosed the failure as a faulty Battery Energy Control Module (BECM) and high-voltage system fault (Code P1E00), requiring a full replacement of the high-voltage battery pack (Part #24296900). The manufacturer (GM) was contacted, and the replacement battery was ordered on July 2, 2025. As of December 2025, the vehicle remains in dealer possession (over 5 months) with no repair completed. The manufacturer has stated the part is on indefinite backorder with no ETA. The failure of this component renders the vehicle inoperable and presents a safety risk due to sudden loss of propulsion power while in motion. The manufacturer has confirmed the failure but is unable to provide a remedy within a reasonable timeframe.

Filed Oct 14, 2025 · Electrical, Fuel system · MO

The car can't decide if it wants to use the battery or the engine. It shows zero charge even though it is full. It lurches at stop lights as it tries to decide whether to use battery or engine. It says "propulsion power reduced". "Not able to charge". "Shift to park". Check engine light is on.

Filed Feb 19, 2025 · Transmission · NC

On [XXX], while traveling on [XXX] near Rockingham, NC, the car suddenly decelerated, all of the dash warning lights came as well as a 'Reduced Propulsion' message, stop driving the car immediately. We did, called a tow truck, waited an hour and was towed to Diffenbach Chevrolet in Rockingham. They found multiple trouble codes and a bulletin saying the EGR valve needed to be replaced. (As it happens, these have been on a nationwide backorder for years.) The technician cleaned the valve and the car limped home after it sat at the dealership for a few weeks. BTW, we missed the Iron Maiden concert we were headed to Charlotte for. We then had the car towed from Southport, NC, to Jeff Gordon Chevy in Wilmington, NC. They had it for a while and stated the part was on back order and with no ETA. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 15, 2025 · Transmission · CA

The Volt experienced a "Shift to Park" error, preventing it from recognizing when it was in park, even when the gearshift was engaged. While this issue was frustrating, it initially didn’t affect the car’s driving capability. I simply had to wiggle the gearshift until the system registered that it was in park. This problem persisted for a month until one day, the vehicle would no longer shift into any mode, though the "Shift to Park" message remained on the dashboard. The car turned on but would not accelerate. The issue was eventually repaired at the dealership, a process that took about two weeks. During this time, we were not initially offered a rental car. It was only after we called and insisted that the dealership provided one while waiting for the necessary parts. This issue appeared to be a factory defect. While part of the repair was covered under warranty, we still had to pay $685 out of pocket.