AutoCodes – GMC – C0027 GMC

C0027 GMC Code - Left Front Wheel Speed Sensor Signal Erratic

Quick Answer

The Anti-Lock Brake System (ABS) Module monitors the Left Front Wheel Speed Sensor. Common causes include Faulty Left Front Wheel Speed Sensor, Left Front Wheel Speed Sensor harness is open or shorted, Left 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: C0027 GMC indicates Left Front Wheel Speed Sensor Signal Erratic.
Common causes: Common causes include Faulty Left Front Wheel Speed Sensor, Left Front Wheel Speed Sensor harness is open or shorted, Left 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 1,736

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 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0027 GMC Description

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

OBDII Code C0027 GMC - Left Front Wheel Speed Sensor Signal Erratic - AutoCodes.com — C0027 GMC Code - Left Front Wheel Speed Sensor Signal Erratic

What does this mean?

What are the Possible Causes of the DTC C0027 GMC?

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

How to Fix the DTC C0027 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 C0027 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.

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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 C0027 GMC Code

1. What are the common symptoms of OBDII code C0027 GMC (Left Front Wheel Speed Sensor Signal Erratic)?

- Common symptoms include ABS warning light illumination, erratic speedometer readings, and potential traction control issues.

2. What can cause the OBDII code C0027 GMC to trigger?

- The code is typically triggered by a faulty left front wheel speed sensor, damaged wiring, or issues with the sensor mounting.

3. How can I diagnose the cause of OBDII code C0027 GMC?

- Diagnose by visually inspecting the left front wheel speed sensor and its wiring for damage, testing the sensor's resistance, and checking the sensor's signal output while the wheel is turned.

4. Can a dirty or faulty tone ring cause code C0027 GMC?

- Yes, a dirty or faulty tone ring can disrupt the signal from the left front wheel speed sensor and lead to the code being triggered.

5. What is the recommended repair for OBDII code C0027 GMC?

- The recommended repair involves replacing the left front wheel speed sensor, repairing any damaged wiring, and ensuring proper mounting and alignment of the sensor.

6. Are there any DIY tips for resolving OBDII code C0027 GMC?

- DIY tips include carefully inspecting the sensor and wiring for damage, cleaning the tone ring if necessary, and ensuring a secure and proper installation of the new sensor.

7. Can driving with OBDII code C0027 GMC cause further damage to the vehicle?

- Driving with this code may affect the performance of the ABS and traction control systems, so it is advisable to address the issue promptly to prevent further complications.

8. Is it safe to continue driving with the ABS warning light on due to code C0027 GMC?

- It is not recommended to drive with the ABS warning light on, as it indicates a potential issue with the braking system that could compromise safety.

9. How long does it take to repair OBDII code C0027 GMC?

- The repair time can vary depending on the extent of the issue and the availability of parts, but it typically takes a few hours to diagnose and replace the left front wheel speed sensor.

10. Can a mechanic reset the OBDII code C0027 GMC after the repair?

- Yes, a mechanic can clear the code using a diagnostic scanner after the repair has been completed to reset the ABS system and ensure the issue has been resolved.