2018 Cadillac XT5: What to check before buying

The transmission shifts itself into Park, usually after idling in Drive for several minutes and then creeping forward. The car comes to a shuddering stop. One report describes it happening while moving with a transmission warning lit, at just 2,900 miles. Other complaints describe the engine shutting off at a stop with no lights, hazards, or screen. Owners also report hard jerks at a stop and at 70 mph, and revs staying high after a downshift. A failed thermostat that sets code P0128 also appears, sometimes along with A/C loss. One crash involves the car rolling backward while stopped.

A "steering assist is reduced" warning dominates, and the wheel gets heavy, especially at low speeds. Dealers repeatedly tie it to code P0128, a thermostat reading coolant below regulating temperature. The warning often arrives along with A/C failure. Reports cluster under 40,000 miles. One driver lost steering control on the interstate after a related sensor repair and crashed, with airbags deployed and injuries. Other complaints cite a popping noise when turning that was traced to the steering column, shaking and StabiliTrak warnings near 68 mph, and a reduced-steering alert fixed with a new battery.

The car shuts off or stalls while driving, sometimes at highway speed. Every warning light flashes, gauges drop to zero, and brakes and power cut out briefly. Dealers often find nothing. Reported fixes include a new battery, a reprogrammed module, and a body control module corroded by condensation from an HVAC water line above it. That module was replaced twice by 95,000 miles. One fire report describes the car burning while being driven, with loss of power steering, and the car was declared a total loss. Other reports cover a thermostat failure that came back after replacement and backup camera guide lines that appear only some of the time.

Loss of motive power is the main pattern. The engine quits while driving or after a stop and sometimes needs several restart attempts. Warning lights are often absent, and mechanics often find no cause. Reported mileages run from 40,000 to 86,000. At 86,000, a dealer said the engine needed replacing. A thermostat fault also triggers the steering assist reduced message and runs the cooling fan at full speed. Other complaints describe the oil percentage reading dropping 1 to 2 points every drive, a recurring check engine light, and a fuel warning that returned after the purge valve and fuel injectors were replaced.

The electronic parking brake locks and will not release. One case required a tow, and other owners report it failing to release more than once. Front brakes squeal at low speed, and the noise returns after service. Single reports describe the car failing to brake at a red light while the engine revved and a parking assist alert flashed. Others describe rear wheels locking with the ABS not working, a brake pedal that is hard to press after the car sits overnight, and a popping sound up front with fault code C056E.

Sharp metal is exposed along the front seat tracks when they sit out of alignment with the base. It has cut toes as people climb out. That single report accounts for both injuries in this category. The manufacturer told the owner the seats function as designed. The second complaint gives no detail beyond an attached document, so the filings show no wider pattern for this category.

Unintended acceleration is the concern. The engine revs high and the car surges when the driver tries to slow or stop. One case ended in a crash into a building wall right after an automated car wash. The other describes the car pushing forward from a stoplight as if holding a cruise speed, though cruise control was never used. That driver needed several brake applications to stop the car. Only two reports exist, so the pattern is thin.

A rear sidewall blew out at 35 mph on the original 20-inch Michelin Touring tires. A dealer replaced all four, and the manufacturer declined warranty coverage. A second report concerns a spare tire of the wrong size, which the manufacturer called normal. That filing names the XTS sedan rather than the XT5. Two complaints are too few to show a pattern.