2015 Cadillac CTS problems

Filed Oct 20, 2026 · Brakes · OR

Component Affected: SERVICE BRAKES Description of Safety Defect & Incidents: Experienced a recurring, systemic mechanical failure within its camshaft-driven brake vacuum assist system, creating an imminent crash hazard on public roadways. On two separate occasions while traveling at operational roadway speeds trying to slow down for an interchange, the vehicle suffered a sudden, catastrophic loss of power brake assistance. The brake pedal instantly became completely rigid, hard pedal, requiring maximum physical exertion to slow the vehicle and drastically extending the emergency stopping distance.Repair History & Manufacturer Involvement: The primary brake vacuum pump was initially replaced by an authorized Cadillac dealership in July 2023. Following that service, the "Brake Assist" warning lamp remained persistently illuminated. I called the dealership to ask how I can reset the warning and no one called me back, so I just lived with it. After driving only approximately 5,000 miles over 3 years, the system completely failed again, causing the second aforementioned on-road moving brake failures.The vehicle was towed back to the authorized Cadillac dealership on June 29, 2026, and has remained continuously out of service in their possession for nearly four months (113+ days) as of late October 2026. Dealership technicians have hit a diagnostic wall. They have repeatedly replaced parts, brake vacuum pump, vacuum sensor hose, brake booster twice during this single visit, and the brake master cylinder. Despite these component replacements, diagnostic fault codes remain active, check engine and brake warning lights remain illuminated, and power braking function cannot be reliably restored.The failure is so severe that the dealership has opened two concurrent General Motors Technical Assistance Center (TAC) cases, and a corporate GM Field Engineer was deployed to inspect the car, which recommended to replace master cylinder on 09/22/2026, no contact since, no loaner.

Filed Oct 6, 2026 · Airbags, Transmission · 143,145 miles · VA

The contact owns a 2015 Cadillac CTS. The contact stated that while driving, the air bag warning light and the check engine warning light illuminated, and the message "Service Vehicle Soon" was displayed. Additionally, the rear end of the vehicle made an abnormal roaring sound. The vehicle was taken to the dealer, where a multi-point inspection was performed. The dealer replaced the purge valve due to a leak, an oil change was performed, and the check engine warning light was reset. The vehicle was taken back to the dealer to be diagnose regarding the roaring sound coming from the rear of the vehicle. The dealer determined that the rear differential was leaking due to a pinion bearing failure and needed to be replaced. The contact associated the failures with the federal safety agency Campaign Numbers: 20V038000 (Power Train) and 26V329000 (Air Bags). The failure mileage was approximately 143,145.

Filed Aug 28, 2026 · Steering · TX

Dash board message power steering service message hard to steer traction assist light is on.

Filed Jul 25, 2025 · Brakes, Engine · 72,000 miles · MD

The contact owns a 2015 Cadillac CTS. The contact stated that while driving at undisclosed speeds, there was a loud grinding and squeaking sounds coming from the vehicle. Additionally, there was a high-pitched sound coming from the vehicle. The contact also stated that the water pump was inoperable. There were no warning lights illuminated. The vehicle was taken to an independent mechanic who determined that the brake pads and rotors needed to be replaced, and the rear differential was leaking. The vehicle was repaired, but the failure recurred. The water pump was replaced under the warranty. The contact stated that the brake pads and rotors needed to be replaced every two months. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 72,000.

Filed Jul 16, 2025 · Transmission · 98,000 miles · NY

The contact owns a 2015 Cadillac CTS. The contact stated while driving 65 MPH, the vehicle shuddered and made an abnormally loud sound. The contact exited the highway and drove to the nearest mechanic shop at a gas station. The mechanic diagnosed the vehicle and determined that the rear differential was fractured and needed to be replaced. The vehicle was being repaired. The contact related the failure to the federal safety agency Campaign Number: 20V038000 (Power Train); however, the VIN was not included in the recall. The dealer and the manufacturer were not notified of the failure. The failure mileage was approximately 98,000.

Filed May 2, 2025 · Steering · 92,000 miles · CA

The contact owns a 2015 Cadillac CTS. The contact stated that occasionally while driving at various slow speeds, the message "Driver Assist Unavailable" and the steering wheel was abnormally firm, requiring excess effort to drive the vehicle until the power steering functionality returned. There was no warning light illuminated. The vehicle was taken to a local dealer, where the vehicle was diagnosed; however, the contact was advised that there was no failure found with the vehicle, and the failure was not duplicated. The vehicle was not repaired. The contact referenced the federal safety agency Campaign Number: 25V175000 (STEERING); as a possible cause for the failure. The manufacturer was not notified of the failure. The approximate failure mileage was 92,000.

Filed Oct 16, 2024 · GA

The car was taken to Hutchinson dealership in Macon Georgia, to have the oil changed and when I went to pick up the car the Cue Screen was cracked. I asked being the car was in their possession they should be liable for the repairs. They told me that there was nothing they can do because there was no Warranty. I asked why would the car need a Warranty in there possession. It's been two year and i can't pay to have it repaired. I'm [XXX] and can't afford to have it repaired. Very sad.....

Filed Oct 4, 2024 · Transmission · 125,000 miles · MD

The contact owns a 2015 Cadillac CTS. The contact stated that there was an abnormal loud clunking sound coming from the rear end of the vehicle while the vehicle was shifting into gears. The vehicle was taken to AMCO Transmissions & Total Car Care, where it was diagnosed that the rear differential had failed and needed to be replaced. The contact stated that the vehicle was previously serviced under the federal safety agency Campaign Number: 20V038000(Power Train); however, the failure persisted. The vehicle was not repaired. The local dealer and the manufacturer were notified of the failure. The failure mileage was 125,000.

Filed Sep 22, 2024 · Acceleration, Steering · AR

The primary issue with the vehicle is the failure of the front transmission pump seal (part #24225543) and the torque converter seal ( part #242337534 ) which caused a significant transmission fluid leak. THe original repair of the torque converter seal was done in Jan 2024 by Andrews Cadillac In Mt Juliet Tn. Failure to properly repair the torque converter seal led to internal damage within the transmission, resulting in the need for a full transmission replacement. THe front pump seal was not replaced as recommended by the service repair manual at the time of the torque converter seal replacement. The faulty component is available for inspection upon request. The safety of myself and others was put at risk due to the vehicle's hesitation to accelerate after stopping, a direct consequence of the low transmission fluid. This hesitation causes a sudden loss of power while driving, increasing the likelihood of an accident. THere is a delay and then a hard shift when off , a significant bump when shifting from first to second gear and when I stop it feels like I've been rear ended by another car. The issue has been confirmed by multiple service centers, including Parker Cadillac, ORR Cadillac, and Christian Brothers Automotive, all of which identified the transmission pump seal as the source of the leak and the resulting damage to the transmission. Additionally, Christian Brothers Automotive found that the torque converter seal was also leaking, further contributing to the vehicle's transmission problems. Despite efforts to have GM engineers inspect the vehicle at ORR Cadillac, they declined. However, Christian Brothers Automotive has provided a thorough inspection and diagnostic of the .There were no warning lamps or error codes indicating the issue, as it was a mechanical failure rather than an electronic one. The symptoms became apparent when the vehicle began hesitating after coming to a stop, and a transmission fluid leak was discovered during the inspection​

Filed May 28, 2024 · Transmission · 157,000 miles · KS

The contact owns a 2015 Cadillac CTS. The contact stated while driving at various speeds, there was an abnormal grinding sound coming from the rear end of the vehicle. The contact also became aware of an abnormal sound near the brake pads; however, the contact stated that the sound was not coming from the brake pads. No warning lights were illuminated. The vehicle was diagnosed by an independent mechanic who determined that the differential needed to be replaced. The vehicle was not repaired. The contact related to the failure to the federal safety agency Campaign Number: 20V038000 (Power Train); however, the VIN was not included in the recall. The manufacturer was not informed of the failure. The failure mileage was approximately 157,000.