2018 Toyota Prius: What to check before buying

Airbags fail to deploy in serious crashes. The reports include a head-on collision at 25-30 mph and a highway side impact at about 70,000 miles. In both cases no warning light came on beforehand, and the car was totaled. One report describes the opposite problem: airbags firing below 5 mph in a parking lot, which caused burns and a crash. Airbag warning lights also come on by themselves. In one case the light was traced to code B1656 and a snapped wire at the driver seat belt buckle.

Windshields crack with no visible impact, either during normal highway driving or while the car sits parked. A pop or a hairline crack quickly spreads across much of the glass. Some owners have replaced the windshield and then seen the new glass crack again. One quote put the replacement at about $900, and a cheap resin repair did not stop the crack from spreading. A separate report describes the moonroof shattering on the freeway, with a glass shard injuring the driver's finger.

Automatic high beams cut out and stay dim, usually after bright oncoming headlights pass or in rain. The system goes dark for anywhere from 25-30 seconds to about 2 minutes. During that time the high beams cannot be turned on by hand unless the automatic feature is switched off, which leaves drivers short of light on unlit rural roads. One dealer reproduced the fault on a second Prius, but Toyota technical assistance calls it normal. Winter drivers also report LED head and tail lights caking over with ice and snow.

Two crash reports filed under this heading describe sudden surging or lost braking at very low speed. Those crashes ended in impacts with a garage and a tree, and one car was declared a total loss. A sunroof also exploded at 45-50 mph on the freeway and was replaced under warranty. Another filing describes the underbody heat shield near the battery, held by four plastic pins, tearing loose over a speed bump. The dealer blamed the driver for that damage. Few of these reports involve the body structure itself.

Sudden forward lurches while creeping into a parking space with the brake applied lead these reports. In one case the car jumped a curb stop and hit a brick wall, injuring the driver. Other reports describe the engine revving while the car does not move away from a stop, in 100F heat with the AC on full. One owner reports the transmission dropping from drive or reverse into neutral more than 10 times. Another complains that the car pulls forward under power as soon as the brake is released.

A "Hybrid System Failure" warning appears at highway speed. It is followed by a check-engine light, an order to pull over, and messages saying power steering and power brakes are shutting off. One dealer fixed a loose cable, but the warning came back. Codes P0113 and P0102 show up at startup along with check-engine and collision-sensor warnings, and one dealer asked for a $110 diagnostic fee even though the car was under warranty. Other filings cover a dead driver door lock actuator and, for the Prius C, a 12V battery with no replacement available.

The brake pedal fails to stop the car in slow, heavy traffic, which leads to low-speed rear-end crashes. One crash came with sudden acceleration and with the pre-collision and brake warning lights on. In another, no warning light came on. Neither the dealers nor Toyota representatives found a brake fault in either case. A separate complaint describes a high-pitched chirp from the brake pedal on a new car that continued after the brake booster was replaced. The dealer called the sound normal.

The driver seat moves forward and back during a rear-end collision. In the one crash report, the driver's knee hit the underside of the dash and the driver's head slammed into the headrest. Afterward the driver could no longer reach the pedals. The front passenger seat stayed in place, and the collision repair estimate did not mention the seat. The only other filing blames the driver seat for severe back pain.