AutoCodes – GMC – B051B 2016 GMC Sierra

B051B 2016 GMC Sierra Code - Right Side Assist Step Motor Control Circuit

Quick Answer

The Assist Step Control (ASC) Module controls the running board actuators to extend or retract the running boards. Common causes include Faulty Right Side Assist Step Motor, Right Side Assist Step Motor harness is open or shorted, Right Side Assist Step Motor circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B051B 2016 GMC Sierra indicates Right Side Assist Step Motor Control Circuit.
Common causes: Common causes include Faulty Right Side Assist Step Motor, Right Side Assist Step Motor harness is open or shorted, Right Side Assist Step Motor circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 195

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 13, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B051B 2016 GMC Sierra Description

The Assist Step Control (ASC) Module controls the running board actuators to extend or retract the running boards. Each actuator consists of an electric motor and a potentiometer. The module supplies a low reference and 10-volt reference source voltage to the potentiometer. The ASC control module monitors the voltage drop across the potentiometer on the position signal circuit. When the actuator shaft rotates, the voltage on the position signal circuit changes. The ASC control module supplies the actuator motor with a 12-volt control circuit and a ground control circuit. The ASC module controls the direction of the actuator by changing the polarity of the control circuits.

OBDII Code B051B 2016 GMC Sierra - Right Side Assist Step Motor Control Circuit - AutoCodes.com — B051B 2016 GMC Sierra Code - Right Side Assist Step Motor Control Circuit

What does this mean?

What are the Possible Causes of the DTC B051B 2016 GMC Sierra?

Faulty Right Side Assist Step Motor
Right Side Assist Step Motor harness is open or shorted
Right Side Assist Step Motor circuit poor electrical connection
Faulty Assist Step Control (ASC) Module

How to Fix the DTC B051B 2016 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

B051B:0B Right Side Assist Step Motor Control Circuit Current Above Threshold
B051B:01 Right Side Assist Step Motor Control Circuit Short to Battery
B051B:02 Right Side Assist Step Motor Control Circuit Short to Ground
B051B:04 Right Side Assist Step Motor Control Circuit Open Circuit

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B051B 2016 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B051B 2016 GMC Sierra Code

What does the OBDII code B051B mean on a 2016 GMC Sierra?

The B051B code indicates an issue with the Right Side Assist Step Motor Control Circuit, which refers to a fault in the electronic control for the motor that moves the right-side assist step.

What are common symptoms of the B051B code on a 2016 GMC Sierra?

Symptoms include the right-side assist step not deploying or retracting properly, unusual noises from the motor, or the assist step being stuck in one position.

What causes the B051B code to appear on a 2016 GMC Sierra?

Common causes include a faulty assist step motor, damaged wiring or connectors in the motor control circuit, or a malfunction in the control module.

Can the B051B code be triggered by a blown fuse?

Yes, a blown fuse in the assist step motor circuit can interrupt power and trigger the B051B code.

How do you diagnose the B051B code on a 2016 GMC Sierra?

Diagnosis involves inspecting the assist step motor, checking the wiring and connectors for damage, testing the circuit for continuity, and scanning for additional trouble codes.

Can the B051B code affect other vehicle functions?

No, this code is specific to the assist step motor and typically does not affect other vehicle systems.

Is the right-side assist step still safe to use with the B051B code present?

If the step is stuck in an extended or retracted position, it may still be usable but could pose a safety hazard if it doesnâ€™t function as intended.

How do you fix the B051B code on a 2016 GMC Sierra?

Repairs may involve replacing the assist step motor, repairing or replacing damaged wiring, or addressing a fault in the control module.

Can the B051B code be cleared without repairs?

Clearing the code without fixing the underlying issue is not recommended, as the problem will likely persist and the code will reappear.

Should the assist step motor be replaced immediately if the B051B code is present?

Not necessarily; the motor should be tested first to confirm it is the cause of the fault, as the issue could also stem from wiring or the control module.