AutoCodes – GMC – U0078 2016 GMC Sierra

U0078 2016 GMC Sierra Code - Control Module Communication Low Speed CAN Bus Off

Quick Answer

The low-speed General Motor Local Area Network (GMLAN) serial data bus is used to communicate information between the devices. Common causes include Check for more codes, Faulty Control Module, Control Module harness is open or shorted. 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: U0078 2016 GMC Sierra indicates Control Module Communication Low Speed CAN Bus Off.
Common causes: Common causes include Check for more codes, Faulty Control Module, Control Module harness is open or shorted.
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 604

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 20, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0078 2016 GMC Sierra Description

The low-speed General Motor Local Area Network (GMLAN) serial data bus is used to communicate information between the devices. The serial data is transmitted over a single wire to the appropriate devices. The low-speed GMLAN serial data circuits also connect directly to the Data Link Connector (DLC). The Diagnostic Trouble Code (DTC) sets when the device setting the DTC has attempted to establish communications on the serial data circuits more than 3 times in 5 s.

OBDII Code U0078 2016 GMC Sierra - Control Module Communication Low Speed CAN Bus Off - AutoCodes.com — U0078 2016 GMC Sierra Code - Control Module Communication Low Speed CAN Bus Off

What does this mean?

What are the Possible Causes of the DTC U0078 2016 GMC Sierra?

Check for more codes
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0078 2016 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 U0078 2016 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 U0078 2016 GMC Sierra code?

Need more information on how to fix the U0078 2016 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 U0078 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code U0078 in a 2016 GMC Sierra?

- Common symptoms may include issues with the vehicle's communication systems, such as intermittent or total loss of communication with various control modules.

2. What can cause the U0078 code to appear in a 2016 GMC Sierra?

- The U0078 code typically indicates a low-speed Controller Area Network (CAN) bus communication problem, which can be caused by wiring issues, faulty control modules, or a defective CAN bus network.

3. How serious is the U0078 code in a 2016 GMC Sierra?

- While the vehicle may still operate, the U0078 code can lead to communication problems between various control modules, affecting the overall performance and functionality of the vehicle.

4. What are some possible repair tips for resolving the U0078 code in a 2016 GMC Sierra?

- Check the wiring harness for any damage, corrosion, or loose connections. Inspect and test the control modules involved in the communication network. Reset the codes and perform a test drive to see if the issue reoccurs.

5. Can I drive my 2016 GMC Sierra with the U0078 code present?

- It is generally not recommended to drive the vehicle with unresolved communication issues as it can lead to further complications and potential safety hazards.

6. How much does it typically cost to repair the U0078 code in a 2016 GMC Sierra?

- Repair costs can vary depending on the exact cause of the issue, but expect to pay for diagnostic testing, potential control module replacements, and labor costs, which can add up to a few hundred dollars or more.

7. Is the U0078 code a common problem in 2016 GMC Sierra vehicles?

- While not extremely common, the U0078 code can occur in 2016 GMC Sierra models due to issues with the low-speed CAN bus communication network.

8. Can I reset the U0078 code in my 2016 GMC Sierra using an OBDII scanner?

- Yes, you can use an OBDII scanner to reset the code after addressing the underlying issue. However, if the problem persists, the code is likely to reappear.

9. Are there any recalls or technical service bulletins related to the U0078 code in 2016 GMC Sierra vehicles?

- It's recommended to check with a GMC dealership or visit the National Highway Traffic Safety Administration (NHTSA) website for any relevant recalls or technical service bulletins related to the U0078 code in your specific vehicle.

10. How can I prevent the U0078 code from reoccurring in my 2016 GMC Sierra?

- Regularly inspect and maintain the vehicle's wiring harnesses, keep control modules updated with the latest software, and address any communication issues promptly to prevent the U0078 code from reappearing.