AutoCodes – Chevrolet – C128B Chevrolet

C128B Chevrolet Code - ABS Master Cylinder Pressure Sensor Offset Error

Quick Answer

The Electronic Brake Control Module uses inputs from the Electronic Brake Control Brake Pedal Position Sensor to determine when the brake is applied and how much force is used. Common causes include Faulty Electronic Brake Control Module (EBCM), Electronic Brake Control Module harness is open or shorted, Electronic Brake Control Module 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: C128B Chevrolet indicates ABS Master Cylinder Pressure Sensor Offset Error.
Common causes: Common causes include Faulty Electronic Brake Control Module (EBCM), Electronic Brake Control Module harness is open or shorted, Electronic Brake Control Module 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 1,186

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 13, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C128B Chevrolet Description

The Electronic Brake Control Module uses inputs from the Electronic Brake Control Brake Pedal Position Sensor to determine when the brake is applied and how much force is used. The Electronic Brake Control Module monitors when the driver's foot is on the brake and locks the offset. The offset is locked when three out of the four inputs indicate the brake pedal is applied. The four inputs are brake pedal travel 1, brake pedal travel 2, master cylinder pressure sensor, and brake pedal position sensor. These inputs are used to determine the driver's braking intent which is used to control the amount of pressure applied to the wheels.
Brake pressure sensor information is communicated from the Electronic Brake Control Module (EBCM) to the Hybrid Control Processor (HCP). This information is used to schedule regenerative braking and engine autostops.
The Diagnostic Trouble Code (DTC) will be set when the Engine Control Module (ECM) detects a corrupted data message from the Electronic Brake Control Module.

OBDII Code C128B Chevrolet - ABS Master Cylinder Pressure Sensor Offset Error - AutoCodes.com — C128B Chevrolet Code - ABS Master Cylinder Pressure Sensor Offset Error

What does this mean?

What are the Possible Causes of the DTC C128B Chevrolet?

Faulty Electronic Brake Control Module (EBCM)
Electronic Brake Control Module harness is open or shorted
Electronic Brake Control Module circuit poor electrical connection
Faulty Starter/Generator Control Module

How to Fix the DTC C128B Chevrolet?

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 C128B Chevrolet 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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Information for Specific Chevrolet Models

C128B 2014 Chevrolet Silverado — ABS Master Cylinder Pressure Sensor Offset Error
C128B 2015 Chevrolet Silverado — ABS Master Cylinder Pressure Sensor Offset Error
C128B 2016 Chevrolet Silverado — ABS Master Cylinder Pressure Sensor Offset Error
C128B 2017 Chevrolet Silverado — ABS Master Cylinder Pressure Sensor Offset Error
C128B 2018 Chevrolet Silverado — ABS Master Cylinder Pressure Sensor Offset Error

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 C128B Chevrolet Code

1. What are the common symptoms of OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

The common symptoms include the ABS warning light illuminating on the dashboard, potential loss of ABS functionality, and possible issues with brake performance.

2. What causes the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

This code is typically caused by a fault in the ABS master cylinder pressure sensor, which may be due to sensor calibration issues, sensor wiring problems, or sensor failure.

3. How can I diagnose the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

Diagnosis usually involves using a diagnostic scanner to retrieve the trouble codes, inspecting the ABS master cylinder pressure sensor and its wiring for any visible damage, and performing sensor calibration tests if necessary.

4. Can I still drive my vehicle with the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

It is not recommended to drive the vehicle with this error code present, as it may affect the proper functioning of the ABS system and compromise braking performance in certain situations.

5. How can I repair the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

Repair options may include recalibrating the ABS master cylinder pressure sensor, repairing or replacing damaged sensor wiring, or replacing the sensor itself if it is found to be faulty.

6. Is it safe to continue driving if the ABS warning light is on due to OBDII code C128B (Chevrolet)?

It is best to avoid driving the vehicle until the ABS issue is resolved, as the system may not function correctly, increasing the risk of skidding or loss of control during emergency braking situations.

7. Can a DIY enthusiast fix the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

While some basic diagnosis steps can be performed by a DIY enthusiast, repairing or replacing the ABS master cylinder pressure sensor may require specialized tools and knowledge best handled by a professional mechanic.

8. How much does it typically cost to repair the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

The cost of repair can vary depending on the extent of the issue and whether sensor recalibration, wiring repairs, or sensor replacement is needed. It is advisable to get a few quotes from reputable repair shops for an accurate estimate.

9. Will resetting the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error make it go away permanently?

Resetting the code may temporarily turn off the warning light, but if the underlying issue with the ABS master cylinder pressure sensor is not addressed, the code is likely to reappear once the system detects the problem again.

10. Are there any preventive maintenance steps to avoid encountering the OBDII code C128B (Chevrolet) ABS Master Cylinder Pressure Sensor Offset Error?

Regularly checking the ABS system for any signs of malfunction, keeping the sensor and its wiring connections clean and free of debris, and following the manufacturer's recommended maintenance schedule can help prevent this error code from occurring.