AutoCodes – Generic – B051B:02

B051B:02 Code - Right Side Assist Step Motor Control Circuit Short to Ground

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:02 indicates Right Side Assist Step Motor Control Circuit Short to Ground.
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 432

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:02 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. The Diagnostic Trouble Code (DTC) will be set when a motor control circuit is shorted to ground.

OBDII Code B051B:02 - Right Side Assist Step Motor Control Circuit Short to Ground - AutoCodes.com — B051B:02 Code - Right Side Assist Step Motor Control Circuit Short to Ground

What does this mean?

What are the Possible Causes of the DTC B051B:02?

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:02?

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:02 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:02 Code

1. What does OBDII code B051B:02 mean?

Code B051B:02 indicates a "Right Side Assist Step Motor Control Circuit Short to Ground," meaning there's an electrical issue causing the assist step motor on the right side to malfunction.

2. What are the symptoms of code B051B:02?

Common symptoms include the right side assist step not deploying or retracting properly, no motor response, or an electrical fault warning on the dashboard.

3. What causes code B051B:02 to trigger?

The code is often caused by damaged wiring, a short circuit in the motor control circuit, a faulty assist step motor, or a defective control module.

4. Can I still drive my vehicle with code B051B:02 active?

Yes, you can still drive the vehicle, but the right side assist step may not function correctly, potentially causing inconvenience or difficulty entering or exiting the vehicle.

5. How do I diagnose code B051B:02?

Start by inspecting the wiring and connectors for damage or corrosion, check for a short to ground in the circuit, test the assist step motor, and verify the control module's functionality.

6. How do I fix code B051B:02?

Repairs may include repairing or replacing damaged wiring, replacing the assist step motor if it's faulty, or reprogramming or replacing the control module if necessary.

7. How much does it cost to repair code B051B:02?

Repair costs can vary but generally range from $100 to $500, depending on whether wiring repair, motor replacement, or module replacement is required.

8. Can a blown fuse cause code B051B:02?

Yes, a blown fuse in the circuit could cause the code by interrupting power to the assist step motor or its control module.

9. How can I prevent code B051B:02 from occurring?

Regularly inspect and maintain the wiring and connectors near the assist step mechanism to prevent damage from debris, corrosion, or wear over time.

10. Do I need special tools to diagnose and repair code B051B:02?

Basic tools like a multimeter for checking electrical circuits and an OBDII scanner to clear the code are typically sufficient, but advanced diagnostics may require specialized tools for testing the motor and module.