B051B
Right side assist step motor control circuit fault
What it means
B051B. Right side assist step motor control circuit fault. The running board cannot extend or retract and the body warning light comes on.. This Chevy-enhanced code applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.
Findings, check these first
- Faulty right side assist step motor
- Motor harness open or shorted
- Poor electrical connection at the motor
- Faulty assist step control module
Standard procedure
- Confirm the code with a scan tool
- Inspect the motor and its connector for damage
- Test the motor circuit for opens, shorts and poor connections
- Command the running board with the scan tool and watch for movement
- Replace the motor or assist step control module only after circuit tests pass
Look up another code
Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.
Sources and review
Review: qualified. Read the source limits below.
- B051B CHEVROLET Code: Meaning, Causes, and Symptoms | OBD2 Codes - OBD2 Codes
live reference page (obd2-codes.co)
Supports: CHEVROLET and GM-family meaning and likely causes for B051B
Fetched directly. B051B reads "Right Side Assist Step Motor Control Circuit".
Last updated 2026-10-02.
Report a correction for B051B. Include your vehicle, the issue and a source if you have one.