FOUR COLD WEATHER PROBLEMS THAT CAN AFFLICT YOUR VEHICLE
Electronic sensors can react in strange ways during winter, Brian Turner writes.
We are all painfully aware of the various complaints our treasured rides give us when Old Man Winter dishes out his best — or worst. Slow engine cranking on startup, creaks and moans from the suspension and almost any other moving part, and frosty interiors are all things we’ve come to expect. But with electronic and mechanical advancements, there are some symptoms you might not expect. Transmissions won’t reach top gear: This relates to automatic transmissions and many now use fluid-temperature sensors to monitor warm-ups and operating temperatures. When the fluid is extremely cold, some controllers won’t allow higher gears or lock up torque converters to engage only when a minimum temperature is reached. This means your instrument panel tachometer will display a higher r.p.m. than you’re used to at a specific road speed. There’s not much you can do to avoid this, except possibly lowering your speed to improve fuel economy, which always takes a major drop with the mercury. Park and collision sensors go wonky: If this one isn’t straightforward, you might need to read your owner’s manual again. Some sensors for parking assistance and collision-prevention systems are in the bumper covers. If they’re packed with ice and snow, they can cause warning lights to illuminate, and chimes or buzzers to play an unpleasant tune.
When sweeping off your chariot after a snowfall, take the time to brush these sensors off. They usually appear as large, button shaped indentations in the bumper covers. Some collision prevention sensors are located behind or on the front grille; if your vehicle has one in that location, clean it as well. When backing up, if you make contact with a snowbank, chances are those sensors will need cleaning again. Anti-lock brakes engaging for no reason: Fortunately, this one got resolved for many vehicles, but there are still a lot of older ones out there that may exhibit this symptom in very unsuspicious circumstances. Anti-lock brake systems use magnetic sensors on each wheel, and when the magnet on the wheel hub rotates around under the sensor, it allows the brake control system to determine wheel speed.
With our winter weather comes low humidity at times and the increased chances of a vehicle developing a static electrical charge from rolling over certain surfaces, particularly dry concrete with lots of metal grates, like you’d find in most parking garages. If a sufficient charge is built up, it can be picked up by the sensors and may cause a momentary burst of the anti-lock hydraulic control unit. It usually won’t apply the brakes, but may initiate a dash warning icon. Diesel exhaust fluid woes: Many diesel owners are used to having to monitor and refill the diesel exhaust fluid (DEF) system. This urea-based fluid is injected into the exhaust on modern diesels to help reduce emissions. This fluid can freeze, hence the fact that all DEF-equipped vehicles have some type of heating system to prevent this from happening. But these heaters can fail, and be overpowered by Mother Nature’s love for deep freezes.
On trucks with exposed undercarriages, this can be a problem during extended cold snaps below -30 C or so. A couple of easy hacks to avoid a trip to the shop for a check-engine light caused by a DEF freeze-up are to park the vehicle in a heated garage for a few hours, or keep an extra jug on hand inside, where it can stay at room temperature. Adding this warm fluid may get you out of a check-engine-light jam.