Tech Tip: Brake pedal sensor causes Chevy Express power loss

Oct. 1, 2024

A customer brought their 2017 Chevy Express in because it lacked power and wouldn't go over 25 mph.

Related To: ALLDATA

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A customer brought in their 2017 Chevy Express claiming it lacked power and wouldn't go over 25 mph. The malfunction indicator light (MIL) was OFF.

Case details

The technician took the van for a test drive to verify the owner’s concerns. Indeed, the vehicle wouldn’t accelerate much past 25 mph, felt like it was starting off in third gear and the engine would rev easily in neutral.

Once back in the shop, the technician connected a scan tool and found the following diagnostic trouble codes (DTCs) in different modules:

ABS - P0110-04 (Pump Motor Circuit Open)
Airbag - B0085 05 (Left Front Side Impact Sensor High Voltage or Open), and B101D 00 (Electronic Control Unit Hardware Malfunction)
BCM - C0277 4B (Brake Pedal Position Sensor Circuit Calibration Not Learned)

The technician didn’t see a reason any of these DTCs would be causing the drivability problem, so he cleared all the DTCs then started studying the parameter identification data (PIDs) on his scan tool. He noticed that one of the brake-system PIDs was reporting 33 percent when it should have been 0 percent.

Confirmed repair

He cleared all the DTCs then conducted a brake pedal position sensor relearn procedure, which reset the brake system PID to 0 percent. After that, he took the van on a test drive. It ran fine with no DTCs in any module. Interesting fix!

About the Author

ALLDATA Tech-Assist Team

The ALLDATA Tech-Assist Diagnostic team is a group of top-notch ASE Master Technicians who have devoted numerous years to the automotive industry as independent shop and dealership technicians, shop owners and a many of them have also been automotive instructors.

Each team member is passionate about helping technicians of all skill levels get vehicles diagnosed and repaired quickly and correctly the first time. Because they help diagnose such a large number of vehicles every day, they are a wealth of experience-based diagnostic knowledge.