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.

NHTSA ID

11740245

Incident

May 15, 2026

Thermostat failure causes steering assist to be reduced. This leaves more difficult steering especially in an emergency situation, thus a safety concern. The vehicle displays a warning: "Steering Assist Is Reduced, Drive with care". An internet search shows this is a well-known problem across all General Motor vehicles. This is also indicated by the technician notes on my repair invoice that a bulletin from the manufacturer has been issued. After restart the warning clears leaving the driver to believe all is well. After a number of miles it reappears.

NHTSA ID

11737788

Incident

May 7, 2026

My windshield has a lot of spider and has never been hit with anything. They spread from the bottom up

NHTSA ID

11729876

Incident

Feb 5, 2026

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.

NHTSA ID

11727656

Incident

Mar 28, 2026

The contact owns a 2018 Cadillac XT5. The vehicle was recently purchased, and while driving at an undisclosed speed, the vehicle failed to accelerate as intended while depressing the accelerator pedal. In addition, the vehicle failed to accelerate above 5 MPH with several unknown warning lights illuminated. The dealer was notified and sent a mobile mechanic to the residence to diagnose the vehicle; however, no cause for the failure was found. The vehicle was towed to the dealer, and it was diagnosed that the emission starter module had failed. The dealer reprogrammed the emission starter module. The contact stated that a week after the repairs were performed, while driving at an undisclosed speed, the vehicle sputtered, and the failure persisted. Several unknown warning lights were illuminated. The dealer was notified of the failure. The vehicle was not inspected or diagnosed due to the cost. The contact stated that the failure persisted, and the vehicle failed to start. The vehicle was no longer able to be started. The contact stated that the vehicle was repossessed but was recovered. The vehicle was towed to the residence and had not been driven since. The manufacturer was not notified of the failure. The failure mileage was approximately 2,000.

NHTSA ID

11725505

Incident

Oct 15, 2025

Mileage

2,000 mi

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

NHTSA ID

11712970

Incident

Jan 19, 2026

Brakes failure. Approaching a busy intersection and facing a red light, I slowed and prepared to stop the vehicle. Nothing happened with regard to braking; instead, the engine seemed to rev up as it continued through the red-lighted intersection with 2 lanes of busy cross traffic from both directions. That there was not a collision is a miracle. I also noticed some flashing displays on the display screen, though hard to take time to read them while avoiding a crash and still trying to stop the car, but I believe they referenced "parking assist." My husband came and drove the car to the dealership (about 3 mi.), and during that drive, there was no braking issue but a Parking Assist readout suddenly appeared, and he was able to return the screen to the map; then a few minutes later, while driving under 20 mph near the dealership there was a notice about "maximum speed" being reached and "parking assist" being somehow reactivated. Vehicle currently at dealership for analysis. Side note: this is our second Cadillac to exhibit this problem -- there should be an NHTSA report on the first (April 2025) -- a 2013 SRX, in which there was a parking lot collision that totaled the vehicle.

NHTSA ID

11703912

Incident

Dec 9, 2025

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.

NHTSA ID

11696390

Incident

Oct 29, 2025

Mileage

40,000 mi

PI to help diagnose A/C concern

This preliminary information communicates information about how to determine if a wheel and tires size change is available.

This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

This Preliminary Information communication provides information to the technician about vehicles that have had multiple repair attempts that are being performed on customer’s vehicles that exhibit vibration conditions without utilizing the support of General Motors Technical Assistance Center. If valid vibration frequency or Road Force Variation data has been collected and a repair attempt does not correct the customer complaint, contact General Motors Technical Assistance Center for further support. For any vehicles that remains unrepaired after being at the dealer for three days or more and a related bulletin or PI is not found, contact General Motors Technical Assistance Center for further support.