AutoCodes – GMC – U0028 2014 GMC Sierra

U0028 2014 GMC Sierra Code - Media Oriented Systems Transport Bus

Quick Answer

The Media Oriented Systems Transport (MOST) bus consists of a physical ring in which multimedia devices share audio, video and infotainment system control data. Common causes include Faulty Audio Unit (Radio), Audio Unit harness is open or shorted, Audio Unit 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: U0028 2014 GMC Sierra indicates Media Oriented Systems Transport Bus.
Common causes: Common causes include Faulty Audio Unit (Radio), Audio Unit harness is open or shorted, Audio Unit 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 275

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 19, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0028 2014 GMC Sierra Description

The Media Oriented Systems Transport (MOST) bus consists of a physical ring in which multimedia devices share audio, video and infotainment system control data. Each device on the MOST bus transmits and receives data via the MOST Bus Serial Data (+/- transmit/receive) circuits. The MOST bus diagnostic master is the Radio. The MOST control circuit is connected to each device on the MOST bus. Each device provides a 12 V signal on the MOST control circuit. The Radio initiates communication on the MOST bus at Ignition ON by toggling the MOST control circuit low for 100 ms. Once each device recognizes the wakeup signal from the Radio on the MOST control circuit, they will respond to the Radio on the MOST bus to indicate no faults are present and normal communications will commence. The Diagnostic Trouble Code (DTC) sets when a fault occurs on transmit, receive, electronic control lines, or internal device failure.

OBDII Code U0028 2014 GMC Sierra - Media Oriented Systems Transport Bus - AutoCodes.com — U0028 2014 GMC Sierra Code - Media Oriented Systems Transport Bus

What does this mean?

What are the Possible Causes of the DTC U0028 2014 GMC Sierra?

Faulty Audio Unit (Radio)
Audio Unit harness is open or shorted
Audio Unit circuit poor electrical connection

How to Fix the DTC U0028 2014 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 U0028 2014 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.

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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 U0028 2014 GMC Sierra Code

What does the OBDII code U0028 mean for a 2014 GMC Sierra?

U0028 indicates a communication issue with the Media Oriented Systems Transport (MOST) bus, which is responsible for transmitting multimedia and data between various components in the vehicle.

What are common symptoms of the U0028 code in a GMC Sierra?

Common symptoms may include malfunctioning audio systems, navigation issues, or problems with other electronic features that rely on the MOST bus for communication.

What could cause the U0028 code to trigger in my GMC Sierra?

Causes can include a faulty MOST bus module, damaged wiring or connectors, a malfunctioning audio unit, or issues with the vehicle's battery or electrical system.

Can I drive my GMC Sierra safely with the U0028 code present?

While you may be able to drive, itâ€™s advisable to address the issue promptly, as it could lead to further electronic failures or loss of multimedia functionality.

How do I troubleshoot the U0028 code on my 2014 GMC Sierra?

Start by inspecting the wiring and connectors associated with the MOST bus for damage or corrosion. Then, check the audio and multimedia components for faults. Using a diagnostic scanner can help identify any additional codes or issues.

Is it necessary to replace the MOST bus module if I get the U0028 code?

Not necessarily. First, verify that there are no wiring issues or simple faults before replacing the module. If other components are functioning correctly, then replacement may be required.

Can I reset the U0028 code myself, and will it fix the problem?

You can reset the code using an OBDII scanner, but this may not fix the underlying issue. Itâ€™s important to diagnose and repair the root cause to prevent the code from returning.

What are the potential costs for repairing a U0028 code issue in a GMC Sierra?

Repair costs can vary widely depending on the issue. Simple wiring repairs may be inexpensive, while replacing the MOST bus module or related components can be more costly, potentially ranging from $100 to over $1,000.

Should I take my GMC Sierra to a dealer for U0028 code repairs?

While a dealer may have the specific expertise and tools for diagnosing multimedia issues, a qualified independent mechanic with experience in electrical systems can also effectively address the U0028 code.