AutoCodes – GMC – U18B9 2015 GMC Sierra

U18B9 2015 GMC Sierra Code - Primary 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: U18B9 2015 GMC Sierra indicates Primary 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 175

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 U18B9 2015 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 U18B9 2015 GMC Sierra - Primary High Speed CAN Bus Subnet Configuration List - AutoCodes.com — U18B9 2015 GMC Sierra Code - Primary High Speed CAN Bus Subnet Configuration List

What does this mean?

What are the Possible Causes of the DTC U18B9 2015 GMC Sierra?

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

How to Fix the DTC U18B9 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 U18B9 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.

Need more information about the U18B9 2015 GMC Sierra code?

Need more information on how to fix the U18B9 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18B9 2015 GMC Sierra 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.

Frequently Asked Questions about U18B9 2015 GMC Sierra Code

1. What is OBDII code U18B9 on a 2015 GMC Sierra?

Code U18B9 indicates a Primary High Speed CAN Bus Subnet Configuration List error in the vehicle's network communication system.

2. What are common symptoms of OBDII code U18B9 in a 2015 GMC Sierra?

Common symptoms of code U18B9 may include issues with dashboard warning lights, erratic behavior of electronic components, and problems with the vehicle's communication system.

3. What can cause OBDII code U18B9 to trigger in a 2015 GMC Sierra?

Possible causes of code U18B9 include damaged wiring or connectors in the high-speed CAN bus network, faulty control modules, or issues with the network communication protocol.

4. How is OBDII code U18B9 diagnosed in a 2015 GMC Sierra?

Diagnosing code U18B9 typically involves using a professional OBDII scanner to retrieve the trouble codes, conducting a visual inspection of the wiring and connectors, and performing network communication tests.

5. What are the repair options for OBDII code U18B9 in a 2015 GMC Sierra?

Repair options for code U18B9 may include repairing or replacing damaged wiring or connectors, reprogramming control modules, or addressing issues with the network communication system.

6. Can I drive my 2015 GMC Sierra with OBDII code U18B9?

It is generally not recommended to drive the vehicle with unresolved OBDII code U18B9, as it may lead to further electrical issues or malfunctions in the vehicle's systems.

7. How much does it cost to fix OBDII code U18B9 in a 2015 GMC Sierra?

The cost of fixing code U18B9 can vary depending on the underlying cause of the issue, the extent of the repairs needed, and labor costs at the repair facility.

8. Is OBDII code U18B9 a serious problem in a 2015 GMC Sierra?

Code U18B9 should be addressed promptly to prevent potential issues with the vehicle's electronic systems and ensure proper communication between control modules.

9. Can a DIY enthusiast repair OBDII code U18B9 in a 2015 GMC Sierra?

While basic troubleshooting like checking wiring connections can be done by a DIY enthusiast, diagnosing and repairing complex network communication issues may require professional expertise.

10. How can I prevent OBDII code U18B9 from occurring in my 2015 GMC Sierra?

Regular maintenance, proper handling of electrical components, and addressing any warning signs promptly can help prevent OBDII code U18B9 and other related issues in your vehicle.