AutoCodes – GMC – B051B 2018 GMC Sierra

B051B 2018 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 2018 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 190

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 2018 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 2018 GMC Sierra - Right Side Assist Step Motor Control Circuit - AutoCodes.com — B051B 2018 GMC Sierra Code - Right Side Assist Step Motor Control Circuit

What does this mean?

What are the Possible Causes of the DTC B051B 2018 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 2018 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 2018 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 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code B051B in a 2018 GMC Sierra related to the Right Side Assist Step Motor Control Circuit?

The common symptoms may include inoperative or malfunctioning right side assist step, difficulty in deploying or retracting the step, and possibly an illuminated warning light on the dashboard.

2. What are the possible causes of OBDII code B051B in a 2018 GMC Sierra?

Potential causes of this code may include a faulty assist step motor, damaged wiring or connectors in the control circuit, a malfunctioning control module, or software issues.

3. How can I diagnose OBDII code B051B in my 2018 GMC Sierra?

Diagnosis typically involves using an OBDII scanner to retrieve the specific fault code, inspecting the wiring and connectors for damage, testing the assist step motor functionality, and checking the control module for proper operation.

4. Can I still drive my 2018 GMC Sierra with OBDII code B051B present?

It is generally safe to drive the vehicle with this code, but you may experience issues with the right side assist step not functioning correctly. It is advisable to address the problem promptly to avoid further complications.

5. How can I repair OBDII code B051B in my 2018 GMC Sierra?

Repairing this code may involve replacing the faulty assist step motor, repairing or replacing damaged wiring or connectors, reprogramming the control module if necessary, and clearing the fault code with an OBDII scanner.

6. Are there any DIY tips for fixing OBDII code B051B in a 2018 GMC Sierra?

While some basic troubleshooting steps can be performed by DIY enthusiasts, addressing this code may require specialized tools and expertise. It is recommended to consult a professional mechanic for a proper diagnosis and repair.

7. Can weather conditions affect the occurrence of OBDII code B051B in a 2018 GMC Sierra?

Extreme weather conditions, such as excessive moisture or temperature fluctuations, may contribute to electrical issues that trigger this fault code. Keeping the vehicle protected from harsh environments can help prevent such issues.

8. Is OBDII code B051B specific to the 2018 GMC Sierra, or can it occur in other vehicle models?

While this code is related to the Right Side Assist Step Motor Control Circuit in a 2018 GMC Sierra, similar issues with assist steps and control circuits can potentially occur in other vehicle models as well.

9. What is the typical cost of repairing OBDII code B051B in a 2018 GMC Sierra at a dealership or repair shop?

The cost of repairing this code can vary depending on the exact cause of the issue, parts needed for replacement, labor costs, and dealership or repair shop rates. It is advisable to obtain a detailed estimate before proceeding with the repair.

10. How often should I expect to encounter OBDII code B051B in a 2018 GMC Sierra?

The occurrence of this code can vary depending on the vehicle's usage, maintenance, and environmental factors. Regular inspection and maintenance of the assist step system can help reduce the likelihood of encountering this issue.