2018 Cadillac XT5

Check engine light sensor came on in mid-May which is the result of a faulty thermostat, also triggering a "Steering Assist is Reduced" message on the dashboard which I consider to be a safety issue. This is a known and common problem for this make, year and model and the cost to fix the problem is very expensive. This issue has been reported by many Cadillac owners on their forum. My mechanic confirmed the problem with the thermostat caused the steering assist is reduced message, along with the air conditioning malfunctioning.

While driving at highway speeds, I needed to accelerate hard in order to pass another vehicle and while accelerating there was a downshift and increase in RPM. After passing, the RPM remained high even after I took foot off accelerator and it seemed the transmission did not shift back out of lower gear, keeping the car traveling at a high rate of speed, endangering myself and other traffic. Applying the brakes would not cause the engine to slow down and the engine kept working hard and traveling fast, causing strain on the brakes to slow down. I pulled over and initially shifted to neutral, but the engine was still revving high (4000 rpm observed). Then I placed the car in park which did not change the high RPM. Then I shut off engine and let it rest. Then I turned auto back on and all was normal. The problem has not yet been reported to dealer but will occur in coming days. There were no prior symptoms, problems, or warning lights on dash display prior to this occurring.

To Whom It May Concern,I am writing to formally report a safety concern involving my 2018 Cadillac XT5, VIN [XXX] . Recently, my vehicle displayed a “Steering Assist Reduced” message on the dashboard while driving. This warning significantly increases the physical effort required to steer the vehicle, especially at low speeds, and I believe it presents a genuine safety hazard.Upon taking the vehicle to an authorized Cadillac dealership, I was informed that the vehicle had stored diagnostic trouble code P0128 (Engine Coolant Temperature Below Thermostat Regulating Temperature). The dealer explained that a malfunctioning thermostat caused the steering assist reduction message to appear. However, at no point did the vehicle illuminate a Check Engine Light, despite the presence of an emissions‑related fault code.I am concerned for several reasons:A critical engine fault (P0128) did not trigger a Check Engine Light, leaving me unaware of any underlying issue. The vehicle reduced power steering assist as a result of an unrelated thermostat malfunction, creating a sudden and unexpected increase in steering effort. This behavior poses a safety risk, particularly in situations requiring quick steering response or low‑speed maneuvering.Cadillac has issued Service Bulletin 17NA158, which acknowledges that thermostat or coolant‑temperature‑related issues can trigger steering assist warnings. This suggests the manufacturer is aware of the problem, yet no recall or corrective action has been issued.Given that steering assist reduction directly affects vehicle control, I believe this issue warrants investigation. A driver should not lose steering assist because of a thermostat fault, nor should a vehicle fail to illuminate a Check Engine Light when a diagnostic code is present.I respectfully request that NHTSA review this matter to determine whether a safety‑related defect exists in the 2018 Cadillac XT5 and similar GM vehicles. Sumitting this for my mother. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOI

The contact owns a 2018 Cadillac XT5. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to coast to the shoulder of the roadway, where the vehicle failed to restart. While attempting to restart the vehicle, the vehicle required several attempts before restarting. After the vehicle was restarted, the vehicle returned to normal functionality, but the failure became a regular occurrence, prompting the contact to discontinue driving the vehicle. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was notified of the failure but provided no assistance. The contact was advised to take the vehicle to the dealer for assistance. The failure mileage was 40,000.

The contact owns a 2018 Cadillac XT5. The contact stated that while driving at an undisclosed speed, the vehicle stalled with the check engine warning light illuminated. The vehicle was towed to the dealer where it was diagnosed that the engine had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 86,000.

I received a Steering Assist is Reduced message and the cooling fan ramped up to full speed. In contacting Cadillac, it seems that it is a below temperature error for the thermostat. Unsure what the thermostat has to do with steering. Also in researching this, this is a wide spread issue and needs to be a recall. My XT5 has 48000 miles on it and the powertrain warranty expired 3 months ago. I believe this should be a recall and should be repaired by the manufacture as it could cause a safety issue while driving.

I was driving on the freeway, came to a stop as traffic increased, then the car shut off m. I had no power, could not get out of the vehicle, no hazards, no tail lights, nothing. I had a complete panic attack, I thought I was going to die. I called OnStar from my cell, they could even locate me. After 30 mins, calling 911, texting the representative from the dealership in which I purchased the car, it turned back on. Either the car was shut off with a signal or there is a serious hazardous issue that needs to be addressed.

When driving the car on Jul 20, the check engine light came on. It went off upon arriving home. We had it checked at our local NAPA Auto Care and they did an Electronic Engine Control Test. The garage did not clear Trouble Codes and advised us to take the car to a dealer. Upon driving the car on Jul 30, the check engine light came on once again. In May 2020, when we had our car in for service, at Sutliff, in State College, PA, they took care of the Engine Control, software issue. This dealer is no longer open so we started taking our car to Blaise Alexander in Altoona, PA We, also, have had several incidents with the Parking Brake not releasing. We took the car to Blaise Alexander, in Altoona, on 3-14-23, and they said that the software showed no problem with the Parking Brake. They advised me to call a tow truck and have it towed into their garage the next time it happened. There is a Cadillac Dealer in Ebensburg, PA which is approx 30 miles away. We are in a dilemma as to have it towed there or have it towed to the GM Dealer in Altoona, PA which is approx 16 miles away. Our car has 50, 813 miles on it. I will have it towed either to the Cadillac dealer or the GM dealer.