AutoCodes – Generic – U18B3

U18B3 Code - Lost Communications With Navigation Control Module On Ethernet Bus

Quick Answer

At the core of the infotainment system is the Radio Ethernet Audio Video Bridging switch which communicates directly to each contributing Infotainment control module terminator. Common causes include Faulty Navigation Control Module, Navigation Control Module harness is open or shorted, Navigation 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: U18B3 indicates Lost Communications With Navigation Control Module On Ethernet Bus.
Common causes: Common causes include Faulty Navigation Control Module, Navigation Control Module harness is open or shorted, Navigation 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 528

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 Jun 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18B3 Description

At the core of the infotainment system is the Radio Ethernet Audio Video Bridging switch which communicates directly to each contributing Infotainment control module terminator. The Ethernet harness consists of twisted pair wires from point to point. Each control module on the Ethernet infotainment system sends/receives data at 100 Mbit/s to/from a specified port at the Radio. The Radio Ethernet will also be used to program USB software update files to the control modules connected to the Ethernet ports. The Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18B3 - Lost Communications With Navigation Control Module On Ethernet Bus - AutoCodes.com — U18B3 Code - Lost Communications With Navigation Control Module On Ethernet Bus

What does this mean?

What are the Possible Causes of the DTC U18B3?

Faulty Navigation Control Module
Navigation Control Module harness is open or shorted
Navigation Control Module circuit poor electrical connection

How to Fix the DTC U18B3?

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 U18B3 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 U18B3 code?

Need more information on how to fix the U18B3 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18B3 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U18B3 Buick — Lost Communications With Navigation Control Module On Ethernet Bus
U18B3 Cadillac — Lost Communications With Navigation Control Module On Ethernet Bus
U18B3 Chevrolet — Lost Communications With Navigation Control Module On Ethernet Bus
U18B3 GMC — Lost Communications With Navigation Control Module On Ethernet Bus

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 U18B3 Code

What does the OBDII code U18B3 mean?

The OBDII code U18B3 indicates a lost communication issue with the Navigation Control Module on the Ethernet bus, suggesting that the vehicle is unable to communicate with the navigation system.

What are common symptoms of the U18B3 code?

Common symptoms include the navigation system failing to operate, GPS signal loss, unresponsive display, and potential issues with related infotainment features.

What causes the U18B3 code to trigger?

The code can be triggered by a variety of issues, including damaged wiring or connectors, faulty Navigation Control Module, problems with the Ethernet network, or software malfunctions.

How can I diagnose the U18B3 code?

To diagnose the code, use an OBDII scanner to read the code and freeze frame data, inspect wiring and connectors for damage, and check for other related codes that could provide additional context.

What are some common repairs for the U18B3 code?

Common repairs include repairing or replacing damaged wiring and connectors, updating or reprogramming the Navigation Control Module, or replacing the Navigation Control Module if it is found to be faulty.

Can I drive my vehicle with the U18B3 code?

While it may be possible to drive the vehicle, you will likely experience navigation and infotainment issues. It's advisable to address the code to restore full functionality.

Is the U18B3 code serious?

While the U18B3 code itself may not affect the vehicle's drivability, it indicates a problem with the navigation system that should be addressed to ensure all features work properly.

Will clearing the U18B3 code fix the problem?

Clearing the code may temporarily turn off the warning light, but it will not fix the underlying communication issue. Proper diagnosis and repair are needed for a permanent solution.

Can I fix the U18B3 code myself?

If you have automotive knowledge, you may be able to troubleshoot and repair wiring or connectors. However, for complex issues like module replacement or reprogramming, it's best to consult a professional.