AutoCodes – Generic – C0640

C0640 Code - Right Front Normal Force Circuit Malfunction

Quick Answer

The Continuously Variable Road Sensing Suspension (CVRSS) module estimates the road surface and communicates that information to the Electronic Brake Control module (EBCM). Common causes include Faulty Electronic Brake Control module (EBCM), Electronic Brake Control module (EBCM) harness is open or shorted, Electronic Brake Control module (EBCM) 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: C0640 indicates Right Front Normal Force Circuit Malfunction.
Common causes: Common causes include Faulty Electronic Brake Control module (EBCM), Electronic Brake Control module (EBCM) harness is open or shorted, Electronic Brake Control module (EBCM) 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 1,853

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 Jul 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0640 Description

The Continuously Variable Road Sensing Suspension (CVRSS) module estimates the road surface and communicates that information to the Electronic Brake Control module (EBCM). The CVRSS module provides a Pulse Width Modulation (PWM) signal to the EBCM through the left and right normal force signal circuits. The CVRSS module sends each normal force value twice to the EBCM. The possible values of the PWM duty cycle are 20%, 40%, 60% and 80%, with the valid range from 10-90%. The EBCM uses this information to provide improved rough-road braking performance.

OBDII Code C0640 - Right Front Normal Force Circuit Malfunction - AutoCodes.com — C0640 Code - Right Front Normal Force Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC C0640?

Faulty Electronic Brake Control module (EBCM)
Electronic Brake Control module (EBCM) harness is open or shorted
Electronic Brake Control module (EBCM) circuit poor electrical connection

How to Fix the DTC C0640?

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 C0640 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 C0640 code?

Need more information on how to fix the C0640 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0640 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C0640 Buick — Right Front Normal Force Circuit Malfunction
C0640 Cadillac — Right Front Normal Force Circuit Malfunction
C0640 Chevrolet — Right Front Normal Force Circuit Malfunction
C0640 GMC — Right Front Normal Force Circuit Malfunction

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 C0640 Code

1. What are the common symptoms of OBDII code C0640 (Right Front Normal Force Circuit Malfunction)?

- Common symptoms include an illuminated ABS light on the dashboard, traction control issues, and potential loss of stability control.

2. What can cause the OBDII code C0640 to trigger?

- This code is typically triggered by a malfunction in the right front normal force sensor circuit, which may be due to damaged wiring, a faulty sensor, or a poor connection.

3. How can I diagnose the cause of OBDII code C0640?

- Diagnosing this code usually involves inspecting the wiring and connections related to the right front normal force sensor, testing the sensor itself, and using a scan tool to retrieve specific data.

4. Can driving with OBDII code C0640 cause any safety concerns?

- Driving with this code may affect the performance of the ABS and traction control systems, potentially compromising vehicle stability in certain driving conditions. It is recommended to address the issue promptly.

5. What are some repair tips for fixing OBDII code C0640?

- Repair tips may include checking and repairing any damaged wiring, replacing the right front normal force sensor if necessary, and ensuring all connections are secure and free of corrosion.

6. Is it possible to reset OBDII code C0640 without addressing the underlying issue?

- Resetting the code without fixing the underlying problem will likely result in the code reappearing once the issue is detected again by the vehicle's diagnostic system.

7. How critical is it to address OBDII code C0640 promptly?

- It is important to address this code promptly to ensure the proper functioning of safety systems like ABS and traction control, which are crucial for vehicle stability and control.

8. Can I fix OBDII code C0640 myself, or do I need a professional mechanic?

- Depending on your automotive repair skills and tools, you may be able to address this code yourself by following diagnostic procedures and repair steps outlined in the vehicle's service manual.

9. Are there any common mistakes to avoid when dealing with OBDII code C0640?

- Common mistakes to avoid include overlooking simple wiring issues, skipping proper diagnostic steps, and resetting the code without resolving the root cause of the malfunction.

10. How can I prevent OBDII code C0640 from recurring in the future?

- To prevent the recurrence of this code, it's essential to perform regular maintenance checks, ensure proper wiring connections, and address any issues promptly to maintain the integrity of the right front normal force circuit.