GM Moves Fast to Fix Hill-Hold Assist Issue in 2011 Heavy Duty Pickups

In less than a week, GM has rolled out a production fix to a problem with the hill-hold assist feature for its 2011 heavy-duty pickup trucks that came to light during our Heavy-Duty Shootout comparison test.

Hill-hold assist automatically applies the vehicle's brakes for 1.5 seconds once you lift your foot off the brake when you're on an incline that’s 5 percent or steeper. It's part of the Chevrolet Silverado's integrated trailer brake controller, so it will apply the trailer's brakes, too, if it has electric brakes.

During our testing on a 7.2 percent grade on July 13, the hill-hold system didn’t engage. The truck rolled backward as soon as we lifted our foot off the brake pedal.

The issue was traced to an incorrect calibration setting in the hill-hold assist system’s software that was quickly diagnosed, and a fix was rolled out to production by Monday.

That’s a remarkably fast update for a production issue, says Jim Hossack, vice president of AutoPacific, an automotive consulting company.

“It’s astounding” that GM could discover and fix an issue like this so quickly, Hossack said. “I think it’s the new GM and technology that wasn’t there a few years ago. It's another feather in GM's cap.”

A GM engineer we spoke with said fixing an issue like this a few years ago could have taken weeks or months. Now, it’s being fixed in days.

While the hill-hold assist calibration settings have been patched in GM’s production HD pickups and those trucks waiting to be shipped to dealers, the company is still studying how it will update the software of trucks already in the hands of customers.

We’ll keep you updated.

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