Motormouth: What's that shudder?
Q: Every now and then when coming to stop signs the brakes on my 2014 Hyundai Sonata will shudder. The dealer mechanic tells me my pads are OK. Is this something I should be concerned about? Is it a dangerous condition?
— D.B., Las Vegas
A: Occasional shuddering is no big deal. But at your car’s age, you may be ready for a brake job. A complete brake job — rather than just replacement pads — includes all the essential hardware (pins, shims, anti-rattle clips etc.). I have a hunch your shudder will be gone for good.
Q: I have a 2006 Lexus SC430 with 74,000 miles on it. Recently I replaced run-flats with new standard tires, which were aligned and balanced. Front struts were also recently replaced. Between 55 and 70 mph only, there is some vibration in the steering wheel. This also occurred prior to the new tires but is less pronounced with the new tires and is not always constant. Any ideas as to the source of the vibration?
— F.B., Chicago
A: Vibration at a specific speed is almost always due to imbalance. But other factors may be the cause. For instance, one of the wheels may not be true. The wheel hub may be a contributor. Or, one of the new tires may be the problem. Have your shop swap the front tires to the rear and see if the vibration goes away or moves to the rear of the vehicle. Otherwise, a suspension inspection is called for.
Q: I thought I would pass along my experience with random TPMS warnings popping up. I discovered that those USB chargers that go into the 12-volt socket trigger an alarm. I plugged in the device and after a while the low-pressure alarm came on. Unplugging the device would, after a few minutes of driving over 20 miles per hour, reset the alarm. The solution came to me after maybe a dozen trips to the dealer for recalibration of the tire sensors. When I picked up my vehicle, the USB charger was unplugged and lying in the cup holder. They never wrote it up on the service ticket or mentioned the USB device to me when picking up the car, but eventually I would need the charger and plug it back in and would get a low tire alarm shorty after.
— B.R., Apple Valley, Minn.
A: We have recently had several readers reporting mysterious low tire pressure warnings and you may have solved the mystery. By the way, with colder temperatures coming, your tires’ cold inflation pressures may drop. Pressure usually drops about one psi for every 10-degree drop in outside temperature. Be sure to bring the tires up to the proper cold inflation pressure shown on the sticker at the driver’s door.
Q: I recently walked away from my 2018 GMC Acadia and carried the key fob with me. The car automatically locks itself, and under normal circumstances this is fine. However, in this instance a passenger was in locked in the vehicle and could not exit. I had no idea that the passenger could not unlock the car from the inside. Warnings about this were not explicit either from the manual or the dealership.
— R.L. Spring Valley, Ill.
A: All vehicles are supposed to have a means of manually unlocking the doors from the inside. Otherwise, as you discovered, a person could be trapped. Try this: Pull the door handle once. This usually releases the lock. Pull it again and the door will usually open.
(Bob Weber is a writer and mechanic who became an ASE-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weber's work appears in professional trade magazines and other consumer publications. His writing also appears in automotive trade publications, Consumer Guide and Consumers Digest.)