AutoCodes – GMC – U18BF GMC

U18BF GMC Code - Secondary High Speed CAN Bus Subnet Configuration List

Quick Answer

The devices on the high-speed General Motor Local Area Network (GMLAN) serial data bus and the chassis high-speed GMLAN serial data bus must be programmed with software that specifically identifies the correct type and quantity of devices on the bus based on RPO configuration. Common causes include Faulty Module that is not configured, Module harness is open or shorted, 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: U18BF GMC indicates Secondary High Speed CAN Bus Subnet Configuration List.
Common causes: Common causes include Faulty Module that is not configured, Module harness is open or shorted, 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 753

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 Aug 09, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18BF GMC Description

The devices on the high-speed General Motor Local Area Network (GMLAN) serial data bus and the chassis high-speed GMLAN serial data bus must be programmed with software that specifically identifies the correct type and quantity of devices on the bus based on RPO configuration. If a device was not properly configured after installation, the appropriate U Code may be set for that device. No external circuit diagnosis is involved. The Diagnostic Trouble Code (DTC) will set when the device is not configured properly, or the device recognizes a programming error.

OBDII Code U18BF GMC - Secondary High Speed CAN Bus Subnet Configuration List - AutoCodes.com — U18BF GMC Code - Secondary High Speed CAN Bus Subnet Configuration List

What does this mean?

What are the Possible Causes of the DTC U18BF GMC?

Faulty Module that is not configured
Module harness is open or shorted
Module circuit poor electrical connection

How to Fix the DTC U18BF 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 U18BF 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 U18BF GMC code?

Need more information on how to fix the U18BF GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18BF GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

U18BF 2014 GMC Sierra — Secondary High Speed CAN Bus Subnet Configuration List
U18BF 2015 GMC Sierra — Secondary High Speed CAN Bus Subnet Configuration List
U18BF 2016 GMC Sierra — Secondary High Speed CAN Bus Subnet Configuration List
U18BF 2017 GMC Sierra — Secondary High Speed CAN Bus Subnet Configuration List
U18BF 2018 GMC Sierra — Secondary High Speed CAN Bus Subnet Configuration List

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 U18BF GMC Code

1. What is the U18BF GMC OBDII code?

The U18BF GMC code refers to Secondary High Speed CAN Bus Subnet Configuration List, indicating a communication error within the vehicle's network system.

2. What are common symptoms of the U18BF GMC code?

Common symptoms include dashboard warning lights, issues with vehicle infotainment systems, and potential loss of communication with various control modules.

3. What can cause the U18BF GMC code to trigger?

The U18BF GMC code can be triggered by damaged wiring, loose connections, faulty control modules, or issues with the CAN bus network communication.

4. How can I diagnose the U18BF GMC code?

Diagnosing the U18BF GMC code involves using a diagnostic scanner to retrieve the fault codes, checking the vehicle's wiring and connections, and testing the control modules for proper communication.

5. Can I drive my vehicle with the U18BF GMC code present?

It is not recommended to drive your vehicle with the U18BF GMC code present, as it may lead to further communication issues among control modules and potentially affect vehicle performance.

6. How do I repair the U18BF GMC code?

Repairing the U18BF GMC code may involve repairing or replacing damaged wiring, securing loose connections, resetting control modules, or reprogramming the CAN bus network configuration.

7. Can a DIY enthusiast fix the U18BF GMC code?

While some basic troubleshooting steps can be performed by DIY enthusiasts, resolving the U18BF GMC code may require advanced diagnostic tools and knowledge, making it advisable to seek professional help.

8. Is the U18BF GMC code specific to certain GMC models?

The U18BF GMC code can be specific to certain GMC models that use a high-speed CAN bus network system for communication between control modules.

9. How much does it cost to repair the U18BF GMC code?

The cost of repairing the U18BF GMC code can vary depending on the root cause of the issue, the extent of damage, and whether any parts need replacement. It is recommended to obtain quotes from professional technicians.

10. Can ignoring the U18BF GMC code lead to other problems in the vehicle?

Ignoring the U18BF GMC code can potentially lead to further communication failures among control modules, affecting various vehicle systems and potentially causing performance issues or safety concerns.