Catching the mistake early may well save you a bundle in repair costs, though repair work may still be required ... your ...

When you press on the brake pedal in your car, for instance, pressurized brake fluid is distributed ... the back of your diesel engine via a controllable valve built into the exhaust system.

Diesel exhaust fluid (DEF) is nothing new. GM’s Duramax-powered Chevrolet Silverado and GMC Sierra 2500HD and 3500HD pickups have had used the stuff since 2011. So has Ford’s F-Series Super Duty.

I recently read a pretty startling statistic—in the next year, the off-highway engine market will consume about 20 million gallons of Diesel Exhaust Fluid (DEF). In the next five years that ...