AutoCodes – Cadillac – C0638 Cadillac

C0638 Cadillac Code - Left Front Normal Force Circuit High

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: C0638 Cadillac indicates Left Front Normal Force Circuit High.
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 1,011

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 C0638 Cadillac 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 C0638 Cadillac - Left Front Normal Force Circuit High - AutoCodes.com — C0638 Cadillac Code - Left Front Normal Force Circuit High

What does this mean?

What are the Possible Causes of the DTC C0638 Cadillac?

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 C0638 Cadillac?

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 C0638 Cadillac 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 C0638 Cadillac Code

What does the OBDII code C0638 indicate in a Cadillac?

C0638 indicates a problem with the left front normal force circuit, which is related to the vehicle's suspension system, specifically the sensor that measures load or weight on the left front corner.

What are common symptoms associated with the C0638 code?

Common symptoms may include warning lights on the dashboard, a rough ride or poor handling, and potential issues with stability control or traction control systems.

What could cause the C0638 code to trigger?

Causes may include a faulty left front suspension sensor, damaged wiring or connectors in the circuit, or issues with the vehicle's control module.

How can I diagnose the C0638 code effectively?

To diagnose the C0638 code, use an OBDII scanner to confirm the code, then inspect the left front suspension sensor and its wiring for damage or corrosion. Testing the sensor's resistance and voltage can also help identify issues.

What repairs are typically needed for the C0638 code?

Repairs may involve replacing a defective left front suspension sensor, repairing any damaged wiring or connectors, or reprogramming or replacing the vehicle's control module if necessary.

Can I drive my Cadillac with the C0638 code active?

While you can drive the vehicle, it's not recommended as it may affect handling and stability. It's best to address the issue promptly to ensure safe driving conditions.

How much does it typically cost to fix the C0638 code?

Repair costs can vary widely, ranging from $50 to $300 for sensor replacement or wiring repairs, depending on labor rates and the specific issue.

Will clearing the C0638 code reset the warning light?

Yes, clearing the code may turn off the warning light temporarily, but if the underlying issue is not resolved, the code is likely to return.

Can the C0638 code affect other vehicle systems?

Yes, since it relates to the suspension system, it can impact other systems like traction control and stability control, potentially leading to further safety issues if not addressed.