AutoCodes – GMC – U18BF 2018 GMC Sierra

U18BF 2018 GMC Sierra 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 2018 GMC Sierra 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 210

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 24, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18BF 2018 GMC Sierra 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 2018 GMC Sierra - Secondary High Speed CAN Bus Subnet Configuration List - AutoCodes.com — U18BF 2018 GMC Sierra Code - Secondary High Speed CAN Bus Subnet Configuration List

What does this mean?

What are the Possible Causes of the DTC U18BF 2018 GMC Sierra?

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

How to Fix the DTC U18BF 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U18BF 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 U18BF 2018 GMC Sierra code?

Need more information on how to fix the U18BF 2018 GMC Sierra code? Get Access to Factory Service Manuals

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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.

Frequently Asked Questions about U18BF 2018 GMC Sierra Code

1. What does OBDII code U18BF mean for a 2018 GMC Sierra?

The code U18BF indicates an issue with the Secondary High Speed CAN Bus Subnet Configuration List in the vehicle's network communication system.

2. What are common symptoms of OBDII code U18BF on a 2018 GMC Sierra?

Common symptoms of code U18BF may include intermittent or total loss of communication with various vehicle modules, warning lights on the dashboard, and potentially erratic behavior of electronic components.

3. What are possible causes of OBDII code U18BF on a 2018 GMC Sierra?

Potential causes of code U18BF can include damaged wiring or connectors in the CAN bus system, faulty control modules, software glitches, or network communication errors.

4. How can I diagnose OBDII code U18BF on my 2018 GMC Sierra?

Diagnosing code U18BF typically involves using a professional OBDII scanner to retrieve the specific details of the fault, checking for any related trouble codes, inspecting the CAN bus wiring and connectors, and performing network communication tests.

5. Can I still drive my 2018 GMC Sierra with OBDII code U18BF?

It is not recommended to drive your vehicle with an unresolved code U18BF, as it may lead to further electrical system issues and potential safety risks. It's advisable to address the problem promptly.

6. How can I repair OBDII code U18BF on my 2018 GMC Sierra?

Repairing code U18BF may involve repairing or replacing damaged wiring, connectors, or control modules in the CAN bus system, updating software if necessary, and clearing the fault codes with a diagnostic tool.

7. Will resetting the OBDII code U18BF on my 2018 GMC Sierra make it go away permanently?

Simply resetting the code without addressing the underlying issue will not make it disappear permanently. It's crucial to diagnose and fix the root cause to prevent the code from reoccurring.

8. Is OBDII code U18BF a common problem in 2018 GMC Sierra vehicles?

While code U18BF may not be as common as some other codes, issues related to the CAN bus system and network communication can occur in various vehicles, including the 2018 GMC Sierra.

9. Can a DIY enthusiast fix OBDII code U18BF on a 2018 GMC Sierra?

Depending on your skill level and access to tools, some DIY enthusiasts may be able to address code U18BF by following diagnostic procedures, inspecting wiring, and making necessary repairs. However, professional assistance is recommended for complex issues.

10. How much does it typically cost to repair OBDII code U18BF on a 2018 GMC Sierra?

The cost of repairing code U18BF can vary based on the specific cause of the issue, labor rates in your area, and whether any parts need replacement. It's advisable to consult a mechanic for an accurate estimate.