AutoCodes – GMC – C1201 GMC

C1201 GMC Code - Left Front Wheel Speed Sensor Circuit Range Performance

Quick Answer

As the wheel is rotated, the speed sensor produces an AC voltage that increases with wheel speed. 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: C1201 GMC indicates Left Front Wheel Speed Sensor Circuit Range Performance.
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 265

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 Nov 19, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1201 GMC Description

As the wheel is rotated, the speed sensor produces an AC voltage that increases with wheel speed. The Electronic Brake Control Module (EBCM) uses the frequency of the AC signal to calculate the wheel speed. The speed sensor is connected to the EBCM by a twisted pair of wires. Twisting reduces noise susceptibility that may cause a Diagnostic Trouble Code (DTC) to be set. The DTC will be set when the left front wheel speed is accelerating or decelerating beyond reasonable limits.

OBDII Code C1201 GMC - Left Front Wheel Speed Sensor Circuit Range Performance - AutoCodes.com — C1201 GMC Code - Left Front Wheel Speed Sensor Circuit Range Performance

What does this mean?

What are the Possible Causes of the DTC C1201 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
Faulty Electronic Brake Control Module (EBCM)

How to Fix the DTC C1201 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 C1201 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 C1201 GMC Code

1. What does the OBDII code C1201 mean on a GMC vehicle?

The code C1201 indicates a problem with the left front wheel speed sensor circuit, specifically that its performance or range is outside the expected parameters.

2. What are the common symptoms of code C1201 in a GMC vehicle?

Symptoms may include the ABS warning light turning on, reduced or disabled ABS functionality, traction control issues, and erratic or inaccurate speedometer readings.

3. What causes the C1201 code to appear on a GMC vehicle?

Common causes include a faulty left front wheel speed sensor, damaged or corroded wiring/connectors, debris interfering with the sensor, or a malfunctioning ABS module.

4. Can I still drive my GMC with code C1201 present?

While the vehicle may still be drivable, the ABS and traction control systems may not function correctly, increasing the risk of skidding or losing control in slippery conditions.

5. How do I diagnose the C1201 code on my GMC?

Diagnosis involves visually inspecting the left front wheel speed sensor and its wiring, checking for debris or damage, and using a multimeter or scan tool to test the sensor's signal output.

6. How do I fix the C1201 code on a GMC vehicle?

Repairs may include cleaning or replacing the left front wheel speed sensor, repairing damaged wiring, ensuring connectors are secure, or replacing the ABS module if necessary.

7. What tools are needed to repair the C1201 code?

Common tools include a scan tool for reading and clearing codes, a multimeter for electrical testing, and basic hand tools for removing and replacing the sensor.

8. How much does it cost to fix code C1201 on a GMC?

Repair costs vary but typically range from $100 to $300, depending on whether the wheel speed sensor, wiring, or ABS module needs replacement.

9. Will clearing the C1201 code solve the problem?

Clearing the code without addressing the underlying issue will only temporarily remove the warning; the code will likely return if the fault persists.

10. Can a dirty wheel speed sensor cause the C1201 code?

Yes, dirt, debris, or rust on the left front wheel speed sensor can interfere with its signal and trigger the C1201 code. Cleaning the sensor may resolve the issue.