Another Example of Ground Side Gremlins
Here’s another great case study by Bob in Massachusetts, this time recounting the diagnosis and repair of a no-start 2016 Chevrolet Express 2500 Work Van. In this case, the only code he had was a U0121 for lost communication with the ABS control module. When he tried to connect to that module, it was showing as offline.
He then began his diagnostic process, starting with checking fuel delivery and fuel pump operation. He then scoped the vehicle’s cranking/starting cycle and saw immediate areas of concern. As you can tell from the headline of this post, the path eventually pointed to a ground issue. Bob breaks down his diagnostic path and where it led. It’s a great case study and well worth your time, especially if you live in an area where rust and corrosion are something you contend with regularly.