2024 Toyota Sienna: What to check before buying

Brakes briefly let go during light, steady pedal pressure, and the van lurches forward until the driver presses much harder. It happens most when rolling to a stop at low speed or braking downhill, with no warning lights. Dealers often cannot reproduce it. Toyota issued TSB 4724 to reprogram the brake actuator, but at least one owner says the fix lasted only about 3 months. One crash with 2 injuries involves a van that would not stop. Separate complaints say the pedal needs heavy pressure in normal stops.

Surging at very low speeds is the main complaint. The van pushes forward while the driver is braking for a stop or creeping through a parking lot, and it takes harder braking to stop it. No warnings appear. One crash involves hard acceleration from about 10 mph that ended with the van hitting a pole. In a different pattern, the van gives no throttle response while crossing traffic, possibly because the forward collision system cuts power, and it leaves the van sitting in the path of oncoming cars.

Power doors and the liftgate cause most of these problems. A power sliding door failed to sense a person in its path and pinched them, causing an injury, and the owner says the problem had happened before. Power liftgates screech, stop opening or closing without help, or open by themselves, even while reversing. For one owner this continued for over 18 months despite repeated dealer visits. A liftgate strut also bent and then burst loudly, throwing its spring and metal parts across the driveway.

Third-row seats do not stay latched when folded. They bounce up over speed bumps, dips, and firm stops, then land with a thud or sit loose a few inches up. One owner reports a broken cable, and dealers have called the behavior normal. Owners worry the seats or cargo on top of them could fly forward in a crash. Separately, a second-row seat left unlatched on its track slid forward under hard braking and slammed into the driver seat, causing an injury.

Sidewall bulges and bubbles are the main complaint. In one case several replacement tires bulged within a week, and the new tires that replaced them bulged again, for six affected tires in total. Owners see bulging sidewalls as a blowout risk. One other report describes a low-tire warning that appeared in a parked van at about 17,826 miles. The dealer blamed the weather and made no repair.

Power cuts out for 2-3 seconds during city driving, and it returns only after the driver pumps the accelerator several times. The owner reports it happening more than once without a known cause, matching hesitation complaints filed under other components. A second report comes from an owner who needed an engine replacement about three months after purchase. The complaint does not give a clear cause and mostly concerns how replacement hurts resale value.

The accelerator stops responding for 2-3 seconds when pulling out from a stop or turning at low speed. The pedal does nothing at any pressure, then the van suddenly moves. No warning lights come on. Owners call it a serious risk when entering traffic with cars coming. One report places the problem at 68,000 miles, and another owner has had it happen twice since buying the van new. Neither had been diagnosed by a dealer when filed.

The driver-side mirror shakes on bumpy roads and at highway speeds, which blurs the reflection and makes headlights hard to judge at night or in rain. The passenger mirror does not do this. A replacement mirror shook just as badly, and dealers called the movement normal. One owner noticed it by 6500 miles. That same owner reports a wavy distortion across the passenger side of the factory windshield, which the dealer also described as normal.