AutoCodes – GMC – C128D GMC

C128D GMC Code - ABS Boost Pressure Sensor Raw Offset Error

Quick Answer

The Electronic Brake Control Module (EBCM) uses input from the boost pressure sensor for more accurate control during brake and vehicle stability enhancement system event. Common causes include Faulty Brake Pressure Modulator, Brake Pressure Modulator harness is open or shorted, Brake Pressure Modulator 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: C128D GMC indicates ABS Boost Pressure Sensor Raw Offset Error.
Common causes: Common causes include Faulty Brake Pressure Modulator, Brake Pressure Modulator harness is open or shorted, Brake Pressure Modulator 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 846

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 Sep 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

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

Code C128D GMC Description

The Electronic Brake Control Module (EBCM) uses input from the boost pressure sensor for more accurate control during brake and vehicle stability enhancement system event. The boost pressure sensor is internal to the brake pressure modulator.

OBDII Code C128D GMC - ABS Boost Pressure Sensor Raw Offset Error - AutoCodes.com — C128D GMC Code - ABS Boost Pressure Sensor Raw Offset Error

What does this mean?

What are the Possible Causes of the DTC C128D GMC?

Faulty Brake Pressure Modulator
Brake Pressure Modulator harness is open or shorted
Brake Pressure Modulator circuit poor electrical connection

How to Fix the DTC C128D 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 C128D 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.

Need more information about the C128D GMC code?

Need more information on how to fix the C128D GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C128D GMC 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.