AutoCodes – GMC – C111B 2018 GMC Sierra

C111B 2018 GMC Sierra Code - Trailer Brake Power Control Module System Voltage

Quick Answer

The Chassis Control Module-Auxiliary receives inputs from the Trailer Brake Power Control Module; these inputs are used to determine trailer connection and the amount of voltage supplied to the trailer brakes. Common causes include Faulty Trailer Brake Power Control Module, Trailer Brake Power Control Module harness is open or shorted, Trailer Brake Power 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: C111B 2018 GMC Sierra indicates Trailer Brake Power Control Module System Voltage.
Common causes: Common causes include Faulty Trailer Brake Power Control Module, Trailer Brake Power Control Module harness is open or shorted, Trailer Brake Power 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 232

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 17, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code C111B 2018 GMC Sierra Description

The Chassis Control Module-Auxiliary receives inputs from the Trailer Brake Power Control Module; these inputs are used to determine trailer connection and the amount of voltage supplied to the trailer brakes. The Diagnostic Trouble Code (DTC) will be set when the Trailer Brake Power Control Module detects a short to ground, open, a short to voltage, or a plausibility failure on the trailer brake output circuit.

OBDII Code C111B 2018 GMC Sierra - Trailer Brake Power Control Module System Voltage - AutoCodes.com — C111B 2018 GMC Sierra Code - Trailer Brake Power Control Module System Voltage

What does this mean?

What are the Possible Causes of the DTC C111B 2018 GMC Sierra?

Faulty Trailer Brake Power Control Module
Trailer Brake Power Control Module harness is open or shorted
Trailer Brake Power Control Module circuit poor electrical connection
Faulty Chassis Control Module-Auxiliary

How to Fix the DTC C111B 2018 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 does this mean?

Code Tech Notes

C111B:03 Trailer Brake Power Control Module System Voltage Below Threshold
C111B:07 Trailer Brake Power Control Module System Voltage Above Threshold
C111B:5A Trailer Brake Power Control Module System Voltage Plausibility Failure

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C111B 2018 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.

Need more information about the C111B 2018 GMC Sierra code?

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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.