In recent weeks, DEF sensor failures have left thousands of trucks parked, with a scarcity of replacement sensors leaving carriers scrambling for solutions.

GM has issued a service bulletin for a DEF sensor problem fix for the 2020 to 2024 GMC Sierra 1500, GMC Sierra HD, and GMC Yukon involving module recalibration.

The DEF level sensor of the affected Chevy Silverado, Tahoe and Suburban vehicles with Duramax engines may read incorrectly, function erratically, or become stuck.

In many cases a DEF sensor failure would cause a vehicle to derate to as slow as 5 miles per hour or become inoperable.

In many cases a DEF sensor failure would cause a vehicle to derate to as slow as 5 miles per hour or become inoperable.

In many cases a DEF sensor failure would cause a vehicle to derate to as slow as 5 miles per hour or become inoperable.