AutoCodes – GMC – U2104 GMC

U2104 GMC Code - Controller Area Network Bus Reset Counter Overrun

Quick Answer

Modules connected to the Controller Area Network (CAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Control Module, Control Module harness is open or shorted, 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: U2104 GMC indicates Controller Area Network Bus Reset Counter Overrun.
Common causes: Common causes include Faulty Control Module, Control Module harness is open or shorted, 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 678

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 Feb 04, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code U2104 GMC Description

Modules connected to the Controller Area Network (CAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. If no communication is detected on CAN serial data circuit, the Diagnostic Trouble Code (DTC) is set. A total non-communication condition may be caused by a short to battery or voltage on any of the CAN circuits or a short between the CAN high and low circuits.
The following modules communicate on CAN serial data bus: The Body Control Module (BCM), The Electronic Brake Control Module (EBCM), The Engine/Powertrain Control Module (ECM/PCM), and The Transmission Control Module (TCM).

OBDII Code U2104 GMC - Controller Area Network Bus Reset Counter Overrun - AutoCodes.com — U2104 GMC Code - Controller Area Network Bus Reset Counter Overrun

What does this mean?

What are the Possible Causes of the DTC U2104 GMC?

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

How to Fix the DTC U2104 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 U2104 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 U2104 GMC code?

Need more information on how to fix the U2104 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U2104 GMC 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 U2104 GMC Code

1. What are the common symptoms of OBDII code U2104 in a GMC vehicle?

The common symptoms of OBDII code U2104 in a GMC vehicle may include issues with the transmission, engine performance, or problems with the vehicle's electronic control modules.

2. What does the OBDII code U2104 GMC indicate?

The OBDII code U2104 for GMC vehicles indicates a Controller Area Network Bus Reset Counter Overrun, which means there is a communication error between control modules on the vehicle's network.

3. What are the possible causes of OBDII code U2104 in a GMC vehicle?

Possible causes of OBDII code U2104 in a GMC vehicle include faulty wiring or connections in the CAN bus system, a malfunctioning control module, or a software issue within the vehicle's network.

4. How can I diagnose OBDII code U2104 in my GMC vehicle?

Diagnosing OBDII code U2104 in a GMC vehicle typically involves using an OBDII scanner to retrieve the code, checking the CAN bus connections, inspecting the control modules, and performing a network communication test.

5. Can I continue driving my GMC vehicle with OBDII code U2104 present?

It is not recommended to continue driving your GMC vehicle with OBDII code U2104 present, as it can lead to further damage to the vehicle's electronic systems and potentially affect its performance and safety.

6. How can I reset OBDII code U2104 in my GMC vehicle?

Resetting OBDII code U2104 in a GMC vehicle involves addressing the underlying issue causing the communication error, fixing any wiring or connection problems, and clearing the code with an OBDII scanner.

7. Is OBDII code U2104 a serious issue in a GMC vehicle?

OBDII code U2104 should be addressed promptly as it can impact the vehicle's overall performance and safety. Ignoring this code may lead to further electrical system malfunctions.

8. Can a DIY enthusiast repair OBDII code U2104 in a GMC vehicle?

While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing OBDII code U2104 in a GMC vehicle may require advanced knowledge and specialized tools. It is advisable to seek professional help for complex issues.

9. How much does it cost to repair OBDII code U2104 in a GMC vehicle?

The cost of repairing OBDII code U2104 in a GMC vehicle can vary depending on the underlying cause of the issue, the extent of the repairs needed, and labor rates in your area. It is recommended to obtain a diagnostic from a certified mechanic for an accurate estimate.

10. Are there any preventive measures to avoid OBDII code U2104 in a GMC vehicle?

Regular maintenance, such as checking and cleaning electrical connections, ensuring proper wiring integrity, and updating software as recommended by the manufacturer, can help prevent OBDII code U2104 and other communication errors in a GMC vehicle.