Four less obvious cold weather side effects on your car

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 start-up, 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, leading to unnecessary visits to your service facility.

Transmissions won’t reach top gear. This relates to automatic transmissions and many now use fluid temperature sensors to monitor warm-ups and operating temps. When the fluid is extremely cold, some controllers won’t allow higher gears or lock-up torque convertors to engage until a minimum temp is reached. This means your instrument panel tachometer will display a higher rpm 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 located 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 your ears 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. And remember – when backing up, if you make any contact at all with a snowbank, chances are those sensors will need cleaning again.

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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 located on each wheel; when the magnet located on the wheel hub rotates around under the sensor, it allows the brake control system (as well as other computers in the vehicle) 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. The problem is 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 in some circumstances get over-powered by Mother Nature’s love for deep freezes. On trucks with exposed undercarriages, this can be a problem during extended periods of a cold snap below -30° C or so. An easy hack to avoid a trip to the shop for a check engine light, caused by a DEF freeze-up, is to either park the vehicle in a heated garage for a few hours or to keep an extra jug on hand inside, where it can stay at room temperature. Adding this warm fluid to aDEF tank may get you out of a check engine light jam.