AutoCodes – Buick – C0640 Buick

C0640 Buick 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 Buick 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 809

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

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

What does this mean?

What are the Possible Causes of the DTC C0640 Buick?

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 Buick?

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 Buick 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 Buick code?

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

Need Help with the Code?

Get the C0640 Buick 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 C0640 Buick Code

1. What does the OBDII code C0640 mean on a Buick?

C0640 refers to a Right Front Normal Force Circuit Malfunction, indicating an issue with the suspension or chassis system, typically affecting the right front shock or strut.

2. What are the common symptoms of the C0640 code on a Buick?

Symptoms may include a warning light on the dashboard, reduced ride comfort, unusual noises from the suspension, or a noticeable difference in vehicle handling.

3. What causes the C0640 code in a Buick?

Common causes include a faulty shock or strut actuator, damaged wiring or connectors in the suspension system, or a malfunction in the control module.

4. Can I drive my Buick with the C0640 code active?

While the vehicle may still be drivable, continuing to drive with this code can lead to further suspension damage and reduced handling performance. Itâ€™s best to address the issue promptly.

5. How do I diagnose the C0640 code on my Buick?

Diagnosis involves inspecting the right front suspension components, checking for damaged wiring or connectors, and using a scan tool to test the suspension control system.

6. How is the C0640 code typically repaired on a Buick?

Repairs may include replacing the faulty shock or strut actuator, repairing damaged wiring, or recalibrating the suspension control module.

7. How much does it cost to fix the C0640 code on a Buick?

Repair costs can vary but typically range from $200 to $800, depending on whether the issue is with the actuator, wiring, or control module.

8. Can a bad sensor cause the C0640 code on a Buick?

Yes, a faulty or misaligned sensor in the suspension system can trigger this code if it fails to provide accurate data to the control module.

9. Will clearing the C0640 code fix the problem on my Buick?

Clearing the code may temporarily turn off the warning light, but it will not fix the underlying issue. Proper diagnosis and repair are required.

10. Is the C0640 code related to the air suspension on a Buick?

Yes, if your Buick is equipped with an air or electronically controlled suspension, the C0640 code could indicate a problem with the actuator or control circuitry for the right front suspension.