2024 CADILLAC LYRIQ Service Brakes Problems

I am submitting this follow-up to document new information and continuing concerns regarding my 2024 Cadillac Lyriq EV, which experienced sudden unintended acceleration during a parking maneuver. GM and its claims administrator (ESIS) have now completed their review and issued a denial letter on October 31 2025, stating “no defects were found.” However, the denial included no supporting technical findings, analysis, or data explaining how that conclusion was reached. Despite multiple written requests, GM has not provided the following key event-data modules: – Brake System Control Module (EBCM/iBooster) export (brake pressure, pedal position, brake override flags) – Propulsion/Drive Control Module data (torque request vs actual torque and accelerator input) – Front Camera Module metadata (timestamps and event record IDs) Additionally, several data discrepancies remain unresolved — including mismatched timestamps between the ASCM and FCM reports and camera images that do not correspond to the actual crash scene. On October 29 2025, GM publicly announced Customer Satisfaction Program N252521980, covering certain 2023–24 Cadillac Lyriq and 2024 Chevy Blazer EV vehicles for a Brake System Control Module software update due to possible brake-control performance issues. Because my incident involved loss of braking response, this recall appears directly relevant. I have requested confirmation whether my vehicle is affected and whether this module was analyzed in GM’s investigation, but have not received a reply. I am requesting that NHTSA review GM’s handling of this case to determine whether the engineering review was complete and whether the vehicle’s BSCM or related systems could be implicated in unintended acceleration or brake override failures. GM Case #1092995 – Submitted to ESIS/GM Product Investigations Group. Thank you for your attention and for documenting this matter in the defect database.

At least 10 times over the past three months the vehicle’s feature of one pedal driving disengages without a reason or code. When the this happens the vehicle accelerates rapidly. This has happened on local streets and on the highway and often results in a near miss collision. I am concerned this will result in a serious injury or death.

I was driving on Saturday September 3 at 5 pm over the Chain Bridge entering Washington DC. Traffic was heavy and the auto brake went on when I was about 15 feet from the car in front of me. I was using one-pedal driving and when I pushed on the gas slowly we started slowly moving forward. I was traveling around 3 or 4 miles an hour and the car would not slow down when I took my foot over the pedal. One pedal driving apparently stopped working. I then applied the brakes gently and the brakes did not work. I then pushed the brakes hard and still no brakes worked. I tried pumping the brakes and nothing worked. The car gently ran into the car in front of me causing no damage to the car in front and he kept on his way. My front grill was cracked and bumper was slightly damaged. The signal on the dashboard said parking brake engaged which it was not. While the auto safety brake engaged minutes earlier when it was not needed it did not work when the car was drifting uncontrollably into the car in front of me.

While driving in one-pedal driving mode at the high setting, an error message appeared and one-pedal driving suddenly shut off and switched to a more standard drive mode where engine braking is disengaged. This happened while drive was engaged and stopped at a red light. The car briefly lurched forward and the car engaged an emergency brake to prevent the car from rolling into the vehicle in front of me. This incident was unpredictable and resulted in an unexpected change to the drive mode I had selected which could have lead to a collision.

I was driving at a steady 65mph on a highway when the car suddenly surged and the message "1 pedal driving deactivated. Use brakes to stop." I stopped the car with the brakes and restarted it and reactivated 1 pedal driving. Note I was NOT using regenerative braking at the time. The car surged a few miles an hour, and in a heavy traffic scenario could have easily caused a crash.

Since a recent software update, vehicle will unexpectedly give multiple error codes, and disengage “one-pedal driving” mode. This happened recently when coming to a stop at a traffic light behind another vehicle. When coming to a gradual one-pedal stop, the one pedal driving mode unexpectedly disengaged, causing me to almost hit the vehicle in front of me. This error has occurred 5-6 times in the past 3 months.

While driving the car on 2 separate occasions, the breaks failed and the car would not stop completely. Twice I have taken the car to the dealer to be repaired and the car is currently at the dealer.

- Software failure resulted in loss of steering control, speed control, and brakes became unavailable. I was on highway car was at 65 mph and then I got a bunch of error messages mentioned below- 1) Steering assist not available 2) AWD is disabled 3) Headlamps not available 4)Service brake assist And then I was not able to brake the car, and steering became highly unresponsive. I took my foot of gas and let the car roll for 1 mile before stopping safely on shoulder, from where I called Cadillac for support (they towed the car back), since error didn't resolve after stopping or rebooting the car. I took screenshot of these errors after stopping and attached them in this email. - Yes it put safety of me, my passenger, and other vehicles at risk, loss speed and steering control you have cause me to hit any other car. - Yes problem is reported to manufacturer, car is in service. - Vehicle is with Service, since no one got hurt, we didn't involve police. - No prior message or warnings we recieved, all errors come as soon as the issues appear.

When it rains, just a steady rain, not a downpour, the vehicle slams on the brakes trying to back up. It literally took 3-4 minutes to back out of the driveway. I was also in a parking lot trying to back out and the same issue which created a significant safety hazard with other vehicles. Research online indicates this is not an isolated issue.

On [XXX], my wife was driving our 2024 Cadillac Lyriq RWD (VIN: [XXX] ) in stop-and-go traffic on [XXX] at 5-10 MPH. She was maintaining a safe distance when the truck ahead suddenly stopped. She pressed the brakes firmly, but the vehicle failed to stop, resulting in a collision. Despite full brake application, the car did not stop as expected. The Automatic Emergency Braking (AEB) and Forward Collision Alert (FCA) systems did not activate. No alerts or braking assistance occurred, even though these safety features were enabled. Her passenger witnessed her screaming that the brakes were not stopping the car. The crash caused front bumper damage, and a police report was filed. Investigation & GM’s Response GM inspected the vehicle but refuses to provide testing details. The Crash Data Report does not show any recorded braking event or safety activation, despite my wife pressing the brakes. GM has not explained: Why the brakes failed to stop the vehicle. Why AEB and FCA did not activate. Why no braking data was recorded despite the collision. Safety Concerns My wife is now afraid to drive the vehicle and refuses to continue driving it after repairs. I may be forced to break my lease or sell the car due to this serious safety concern. This raises major safety risks for other Cadillac Lyriq owners, especially with known braking-related recalls on 2023 and 2024 models. Request for Investigation I urge NHTSA to: Investigate braking system failures in the 2024 Cadillac Lyriq. Review AEB and FCA non-activation during low-speed collisions. Determine whether GM is withholding data or failing to acknowledge a defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving northbound on [XXX], south of Oklahoma City, at normal highway speed, at night, in the rain (on [XXX]), this EV lost all power to the wheels and the regenerative braking ceased to function. It appears that all flow of electrons from the batteries to the drive motors, and from the regenerative brakes to the batteries stopped. I still had dashboard lights, steering, and conventional brakes. I was able to safely coast to a stop on the highway shoulder. I set the parking brakes, put the “transmission” into “park”, and turned off the power button. I then restarted the car, and all was normal again. I continued my drive from Austin, TX, to Evergreen, CO with no additional incidents, arriving on [XXX]. This is reminiscent of the “blue screen of death” in old Microsoft desktop computers — fixed the problem by cycling the ON / OFF switch. Unfortunately, doing this when driving at 75 mph is less than ideal, and is a real potential safety problem. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving through Wisconsin on [XXX] with Super Cruise activated in 70MPH traffic the car provided me with driver's side collision warning failure notice and then a forward collision warning failure notice, but the car continued to be operating normally. A short time later a brakes overheating warning came on while the car still seemed to be operating normally and maintaining speed. I immediately disengaged the cruise control to check out the situation and the car instantly locked on the brakes, and we could see smoke and smell the burning brakes. I pulled to car to the side of the road, and we exited the car concerned there might be a fire coming from one of the 4 smoking wheels. The rotors were red hot. We remained a safe distance from the car until the brakes stopped smoking. After it appeared safe, I reentered the car and determined the brakes (parking brakes) were fully engaged and the car would not move. We contacted OnStar for assistance and waited. After a significant time (it seemed like quite a while) I suddenly heard the sound of the parking brakes electrically releasing. Shortly after that I started and tested the car again and it would move so we slowly drove it off the busy interstate to the next exit a short distance away and continued working with OnStar to obtain a tow to a Cadillac dealership. After working with OnStar for several hours and determining that there would most likely be no tow truck coming, we decided to test drive the car around the area now that the brakes had cooled off. We ended up renting a 'safety' car that my wife would drive, and I would try to drive the car back to Minnesota to our dealer. The car operated normally for the drive home, but we did not use any cruise control just in case. It was my belief that a system communication issue told the brakes to engage and that since the Super Cruise was engage the motors just added more power to over-come the drag on the brakes until they over heated. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION AC

When approaching a red light at 5-10mph, I engaged the brakes, but the brakes did not work and the automatic breaking didn't work either, leading me to rear end the car in front of me. There were no prior warnings lights or notices, and the breaks were working properly before and after the accident. The car was towed to the dealership for inspection, but they could not find anything wrong and have contacted GM for further inspection.

I was driving the car on the turnpike and out of nowhere the rear collision system went offline and the automatic breaking was triggered while I was going 70 mph in rush hour. The brakes started to smoke and smell and the the warning of ‘breaks overheating. do not drive. call service’ happened. I proceeded to narrowly avoid many cars on the road by having to cross three lanes of traffic over to the shoulder and the car was fully smoking, I quickly turned it off I got out and stepped away. After some time when I felt safe returning to the vehicle I turned it back on and was still showing breaks were overheated message and then was forced to get the car towed and take an Uber home. The vehicle is only 2 months old with ~3300 miles on it. The vehicle is currently sitting at the closest dealership to the event and they are unable to work on it due to a lack of EV service provided there and they told me they are unable to have it moved to the dealership I purchased it at.

As I approached a stop sign and hit the brake the car did not stop. I pounded on the brake but there was no response at all; it just coasted forward. The car continued to move and hit the car in front of me stopped at the stop sign. That car, a Nissan Rogue, had no damage. I was barely moving but the plastic sheet in the front of the Lyriq was cracked.

There was “Brake System Failure” message on the EV’s digital display. It happened 3 times in less than a month. When it happened, I had to apply the break very hard. Otherwise, the car would not stop completely and would not hit the car in front. Top speed is limited 43 mph so I could not drive it on freeway.

Without warning and while driving this vehicle on expressway, I've received the following notifications several times: "Brake Failure" (car brakes on its own); "Service Stability and Auto Hold"; and "High Voltage" and Battery. Brakes, speed, steering, parking systems and camera do not work properly. Car's capacity to drive vehicle safely is reduced significantly - speed to drive car is immediately reduced and is limited without warning. Car shakes passengers violently (whiplash) when it believes there are people or objects in its path when there is nothing there and does not work properly when pedestrians are around the vehicle. During the incidents both my safety and other drivers safety are at risk - I am afraid to drive this vehicle although the dealership has indicated they have corrected the errors.Vehicle purchased 23 Oct - problems began around 2300 miles and have continued thru 4200 miles.

When in reverse abrupt automatic braking occurs. Safety hazard with abrupt stop around other vehicles, hard braking causes driver and passenger to pitch forward. No warning. Automatic Braking disabled, sensors checked, settings adjusted by dealer. Dealer says there is nothing they can do. General Motors contacted but no action taken to date.