Cadillac CT5 check engine light comes on

Filed Mar 3, 2026 · Transmission · 578 miles · TX

The contact owns a 2020 Cadillac CT5. The contact stated that while driving at various speeds, the vehicle shuddered and experienced hard shifts intermittently. There was no warning light illuminated. The contact stated that the failure progressively worsened, and the vehicle made an abnormally loud sound while driving. The check engine warning light and the traction control warning light were illuminated. The contact stated that after taking the transmission apart, the contact became aware that cheaply made transmission parts had disintegrated, and there were metal shavings in the transmission. The contact determined that the transmission needed to be replaced; however, it was an extensive repair. The contact had received notification of the federal safety agency Campaign Number: 25V148000 (Power Train); however, the recall repair only involved the transmission control module monitoring software installation. The dealer was contacted and informed the contact that the transmission repair was not covered under the recall. The contact stated that the recall remedy was inadequate to correct the failure. The vehicle was not repaired. The manufacturer was contacted and informed the contact that the recall repair could not be performed on the vehicle due to the vehicle having a branded title. The failure mileage was approximately 578.

Filed Feb 17, 2026 · Acceleration, Engine · OK

Catastrophic engine failure within 700 miles Requires full engine replacement Problems began around 150 miles on odometer Message: Reduced accelerated speed Check engine light Service transmission system Service variable valve timing system

Filed Feb 12, 2026 · Engine, Wheels · CA

While driving on a very busy highway going downhill when suddenly the vehicle started feeling abnormal like it was going to turn off automatically, heard an abnormal grinding noise coming from the engine the vehicle dropped speed drastically and the check engine light turned on , luckily we were on a part of the road where I merged quickly to the side of the road followed by a sudden engine shut down, the safety of myself and 3 other passengers was very compromised due to nearly being hit by other vehicles coming at a high speed on a main highway when my vehicle suddenly slowed down coming to a shut down due to the engine failure, I attempted to turn the car on again but would not turn on, was not getting any response at all, had to get the car towed, the vehicle did not have other warning lights before the failure, the check engine light came on after the engine failed, the vehicle was taken to an authorized Cadillac dealer where the engine was diagnosed as Engine seized, locked up and will not turn over. I received a Recall regarding Momentary Wheel Lock-Up which leads me to believe that might be related to what happened to my vehicle but did not have 8K dollars for a teardown to further inspect the root cause of my engine failure and definitely did not have over 11K dollars for a new engine/labor cost. The Cadillac dealer was quick to deny the possibility to be related to the recall without even doing a teardown of engine also the dealer denied the option to work on the recall repair due to the vehicle being inoperable.

Filed Dec 16, 2025 · Body, Electrical · 75,000 miles · TN

The contact owns a 2020 Cadillac CT5. The contact stated that the check engine warning light was illuminated. The contact had noticed an oil leak and that the battery charge was abnormally low. The contact received an alert from OnStar pertaining to the critically low battery. Additionally, the contact noticed that there was an abnormal squishing sound coming from the dashboard, and the contact believed that the sound was coming from an animal that had intruded into the vehicle. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The vehicle was taken to a tire center where all four TPMS sensors were replaced. The failure mileage was approximately 75,000.

Filed Nov 18, 2025 · Engine · 14,466 miles · WI

The contact’s son owns a 2020 Cadillac CT5. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated. After a visual inspection, the contact observed that the engine oil was abnormally low. The vehicle was taken to the dealer, who diagnosed a failure with the engine. The contact was informed that the engine needed to be replaced. The vehicle was repaired, but the failure reoccurred. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the federal safety agency Hotline for assistance. The failure mileage was 14,466.

Filed Sep 3, 2025 · Transmission · MI

The valve body in the ten speed transmission failed while driving. The transmission did a rough shift and a message popped up on the display saying that power has been reduced along with the check engine light illuminating. The transmission reduced usable gears to prevent damage. I was a hazard on the road way due to not being able to get up to the posted speed limit. The car is at Harvey Cadillac (the dealership I purchased the car from) and I have been told GM is going to replace the transmission under warranty.

Filed Jul 8, 2025 · Transmission · 12,000 miles · KY

The contact owns a 2020 Cadillac CT5. The contact stated that while driving at various speeds, the transmission was slipping while shifting gear. Additionally, the contact stated that there was a delay while shifting gear. The check engine warning light remained illuminated intermittently. The vehicle was taken to a local dealer where the vehicle was diagnosed, and the contact was advised that there was no failure found with the vehicle. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 12,000.

Filed May 15, 2025 · Transmission · IL

At 22,000 miles, driving along at approximately 40mph, vehicle felt like it surged - check engine light went on and message of "limited acceleration - drive with care" appeared. Key cycled the car, CEL and message remained. Car would then not drive higher than 3rd or 4th gear and at limited speed as I tried to get it home. Once I pulled into my driveway message appeared "Service Transmission Now - Unable to Shift Soon." Car would then not move when shifted into any gear, including reverse. Had vehicle towed to dealer where they found the transmission valve body needed to be replaced. There are no available parts anywhere in the country and was told this could be a long wait for repair. Upon searching, there are 2020-22 GM vehicles with similar issues like Chevy and GMC where they have recalled the valve body, but the 2023 Cadillac CT5-V is not included in this and likely should be. My dealer told me my CT5 is not the only one they have currently waiting on this exact part.

Filed Apr 11, 2025 · Engine, Fuel system · GA

Safety Concerns and Defects: I am reporting several safety-related defects in my 2020 Cadillac CT5, which have posed serious risks to me and my family: ⸻ 1. Transmission Pump Failure: •The transmission pump failed, causing loss of power and jerking while driving at highway speeds. This occurred on[XXX] in Georgia with my two small children in the car, putting us at high risk of a crash. •No warning lights appeared, and the failure was diagnosed by the dealer (Hennessey Cadillac). 2. EVAP System Failure (P0451): •A fuel tank pressure sensor malfunctioned, triggering a check engine light shortly after purchase. This affects emissions and presents a fire risk due to potential fuel vapor leaks. •The issue was confirmed by the dealer. 3. Camshaft Solenoid Failure (P0027): •A camshaft solenoid failure was repaired by the dealer, but was not disclosed to me at purchase. •This could have caused engine stalling or hesitation. ⸻ Has the Issue Been Confirmed? •Yes, all issues have been confirmed by the dealership. The vehicle has been returned for repairs, and I can provide diagnostic and repair records. ⸻ Safety Risk and Urgency: The transmission failure almost caused a serious accident on a highway. These defects present imminent safety risks that need investigation. I believe other owners may face similar issues. ⸻ Request for the federal safety agency Action: Please investigate these defects in the 2020 Cadillac CT5, particularly the transmission pump failure, EVAP system, and engine stalling risks. Thank you for your attention to this matter. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Dec 19, 2023 · Acceleration, Engine · CA

this vehicle has had multiple check engine failures it has been in for service six times in a matter of months. In September I had Service Traction control/StabiliTrack lights come on and the car losses of engine power. I had it serviced again in October for the same issue it was at the dealership for 20 days all they did was clear the code and drove it 38 miles, including the technician driving it home to see if the issue could be duplicated. After the 20th day they advised me to pick up my vehicle and return it when the light were actively on. I expressed to them as well as GM that I felt unsafe driving my vehicle this way as it is a great danger to my safety when the car looses power. I drive up/down a canyon as early as 3am I went from speeds of 80mph drooped down to 20-25mph due to this failure. Today I have another check engine light on the vehicle. I dont feel safe driving this vehicle at all!