2025 Tesla Model S: What to check before buying

The driver-assist computer, called AP4, fails on nearly new cars and takes down every camera, the backup camera, GPS navigation, cruise control, lane keeping and automatic emergency braking at once. Several cars had under 1,000 miles. Owners describe weeks-long service waits and back-ordered parts. Other reports cover a horn that goes quiet in rain, a touchscreen that goes black until a hard reboot, and a front trunk lid that flies open at highway speed. Two filings involve fire, including smoke from the vents followed by flames in the dash. Most excerpts describe Model Y and Model X cars.

Hard, unexplained braking is the main complaint. Cruise control or Autopilot brakes sharply for vehicles in adjacent lanes, curve signs, or turning cars at a safe distance, raising rear-end risk. A Curvature Assist message appears on straight roads and cuts speed suddenly. Other reports describe Autopilot or Full Self-Driving veering toward adjacent traffic or into oncoming lanes. The AP4 computer failure also shows up here, disabling cameras and collision warnings within the first few hundred miles. Two filings are crash-related, one at 55 mph into roadside posts. Most excerpts describe Model Y and Model X cars.

Sudden hard braking with nothing ahead is the most common report, and two drivers describe whiplash from it. Automatic emergency braking switches itself back on every drive even after being turned off. Other filings describe the car not stopping despite firm pedal pressure, rolling forward while parked on a snowy driveway, and regenerative braking, traction control and stability control dropping out at random. One-pedal regenerative braking cannot be turned off, which owners call unsafe on ice. Two filings are crash-related. Most excerpts describe Model Y and Model X cars.

Lane-keeping failures under Full Self-Driving or Autopilot account for the most serious reports. The car leaves its lane and hits a divider, guard rail or tree, in one case disengaging about 1 second before impact. Four of seven filings are crash-related, with three injuries. A "Steering Assist reduced" alert leaves the wheel extremely hard to turn, forcing a tow on a car under 20 days old. The turn-signal button on the wheel or yoke works only intermittently, even after yoke replacement. Most excerpts describe Model Y and Model X cars.

Unintended acceleration at low speed is the main pattern. The car lunges forward or shoots backward when shifted, when the brake is released, or during automatic parking, striking bollards, trees and garage contents. Three of six filings are crash-related, with three injuries. Other complaints say a Full Self-Driving update removed driver-set speed targets and that the system misreads speed limits by as much as 25 mph, causing abrupt speed changes. One report ties an AP4 computer failure to lost cameras and safety features within 700 miles. Most excerpts describe Model Y cars.

Cameras and driver aids drop out when the AP4 computer fails, leaving no backup camera, GPS, collision warning or lane departure warning. One report adds side mirrors stuck dimmed in daylight. Failures arrive within weeks of delivery, then repair dates slip for weeks with no loaner offered. Three filings are crash-related: Full Self-Driving clipping a truck while changing lanes, the system shutting off mid-turn at highway speed, and the car backing into a parked car without any warning. Most excerpts describe Model Y cars.

Airbags fail to deploy in serious crashes. Three of four filings are crash-related, covering a T-bone collision that totaled the car, a high-speed side impact, and a 30 mph frontal hit into a tree. Two reports add that seat belts did not lock or retract. Another owner reports a front left safety restraint warning and a service wait of at least 10 days. Two filings report injuries. Most excerpts describe Model Y cars.

Windshields crack when defrost runs in extreme cold, and owners say Tesla declines to cover the glass. Camera-based automatic wipers miss light rain and swipe a dry windshield, smearing bugs and sap. Turning them off does not stick, because they switch back on whenever Autopilot or Full Self-Driving is engaged. A third filing repeats the AP4 computer failure that disables cameras, driver aids and navigation. No crashes or injuries are reported in this category.