AutoCodes – GMC – C0021 GMC

C0021 GMC Code - Right Front Wheel Speed Sensor Circuit Open Or Shorted To Battery

Quick Answer

The Anti-Lock Brake System (ABS) Module monitors the Right Front Wheel Speed Sensor. Common causes include Faulty Right Front Wheel Speed Sensor, Right Front Wheel Speed Sensor harness is open or shorted, Right Front Wheel Speed Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: C0021 GMC indicates Right Front Wheel Speed Sensor Circuit Open Or Shorted To Battery.
Common causes: Common causes include Faulty Right Front Wheel Speed Sensor, Right Front Wheel Speed Sensor harness is open or shorted, Right Front Wheel Speed Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,995

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0021 GMC Description

The Anti-Lock Brake System (ABS) Module monitors the Right Front Wheel Speed Sensor. The ABS Module sets the OBDII code when the Right Front Wheel Speed Sensor is not to factory specifications.

OBDII Code C0021 GMC - Right Front Wheel Speed Sensor Circuit Open Or Shorted To Battery - AutoCodes.com — C0021 GMC Code - Right Front Wheel Speed Sensor Circuit Open Or Shorted To Battery

What does this mean?

What are the Possible Causes of the DTC C0021 GMC?

Faulty Right Front Wheel Speed Sensor
Right Front Wheel Speed Sensor harness is open or shorted
Right Front Wheel Speed Sensor circuit poor electrical connection

How to Fix the DTC C0021 GMC?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0021 GMC 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.

Need more information about the C0021 GMC code?

Need more information on how to fix the C0021 GMC code? Get Access to Factory Service Manuals

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Get the C0021 GMC code diagnosed by a professional: Find a repair shop in your area

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 C0021 GMC Code

1. What are the common symptoms of OBDII code C0021 GMC?

The common symptoms of code C0021 GMC include ABS warning light illuminated on the dashboard, traction control system malfunction, and potential loss of anti-lock brake system functionality.

2. What does the OBDII code C0021 GMC mean?

OBDII code C0021 for GMC vehicles indicates a Right Front Wheel Speed Sensor Circuit Open or Shorted to Battery, suggesting an issue with the electrical circuit of the right front wheel speed sensor.

3. What are the possible causes of OBDII code C0021 GMC?

Possible causes of code C0021 GMC include a damaged or faulty right front wheel speed sensor, a short circuit in the sensor wiring, corrosion in the sensor connector, or an issue with the ABS module.

4. How can I diagnose the OBDII code C0021 GMC?

Diagnosing code C0021 GMC involves inspecting the right front wheel speed sensor and its wiring for any visible damage, testing the sensor's resistance, checking the sensor signal with a scan tool, and verifying the sensor's output using a multimeter.

5. Can I still drive my vehicle with OBDII code C0021 GMC?

It is not recommended to drive your vehicle with code C0021 GMC present, as it can affect the proper functioning of the anti-lock braking system and traction control, compromising your safety on the road.

6. How do I repair OBDII code C0021 GMC?

Repairing code C0021 GMC typically involves replacing the right front wheel speed sensor if it is faulty, checking and repairing any damaged wiring or connectors, and clearing the code with a scan tool.

7. Will resetting the OBDII code C0021 GMC make it go away permanently?

Resetting the code may temporarily clear the warning light, but if the underlying issue causing code C0021 GMC is not addressed and repaired, the code is likely to reappear.

8. Can a DIY enthusiast fix OBDII code C0021 GMC at home?

Depending on your experience and access to tools, a DIY enthusiast may be able to fix code C0021 GMC at home by following proper diagnostic procedures and replacing the faulty components.

9. How much does it cost to repair OBDII code C0021 GMC at a mechanic or dealership?

The cost of repairing code C0021 GMC at a mechanic or dealership can vary depending on the labor rates, parts needed, and the specific cause of the issue, but it typically ranges from $100 to $300.

10. How urgent is it to address OBDII code C0021 GMC?

It is important to address code C0021 GMC promptly to ensure the proper functioning of your vehicle's anti-lock brake system and traction control. Ignoring the issue can lead to potential safety risks and further damage.