C128B 2015 GMC Sierra 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 2015 GMC Sierra 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.
Code C128B 2015 GMC Sierra Description
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.
What are the Possible Causes of the DTC C128B 2015 GMC Sierra?
- 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 2015 GMC Sierra?
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 2015 GMC Sierra 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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Frequently Asked Questions about C128B 2015 GMC Sierra Code
What does the OBDII code C128B mean for a 2015 GMC Sierra?
The C128B code indicates an ABS Master Cylinder Pressure Sensor Offset Error, suggesting a fault with the sensor that monitors brake pressure.
What are the common symptoms of code C128B in a 2015 GMC Sierra?
Symptoms include an illuminated ABS warning light, reduced braking performance, and possibly a loss of traction or stability control functions.
What causes the C128B code to appear in a 2015 GMC Sierra?
Common causes include a malfunctioning master cylinder pressure sensor, wiring issues, or a fault in the ABS module.
Can I drive my 2015 GMC Sierra with the C128B code active?
Driving is possible but not recommended, as ABS and stability control systems may be compromised, increasing the risk of an accident.
How can I diagnose the C128B code on a 2015 GMC Sierra?
Use a scan tool to verify the code and check the master cylinder pressure sensor readings. Inspect sensor wiring and connections for damage or corrosion.
How do I fix the C128B code on a 2015 GMC Sierra?
Repairs may include replacing the master cylinder pressure sensor, repairing damaged wiring, or reprogramming or replacing the ABS module.
How much does it cost to repair the C128B code in a 2015 GMC Sierra?
Repair costs can vary but typically range from $150 to $500, depending on whether the sensor, wiring, or ABS module needs replacement.
Can a low brake fluid level cause the C128B code in a 2015 GMC Sierra?
Low brake fluid does not directly cause this code but may impact braking performance and trigger other related issues.
Will resetting the ABS system clear the C128B code on a 2015 GMC Sierra?
Resetting the ABS system may clear the code temporarily, but the underlying issue must be addressed for a permanent fix.
Is the master cylinder pressure sensor difficult to replace on a 2015 GMC Sierra?
Replacing the sensor may require moderate technical skill and tools but is generally manageable for experienced DIYers or qualified mechanics.
Discuss the causes and fixes for C128B 2015 GMC Sierra OBDII Code
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