AutoCodes – Chevrolet – U0078 Chevrolet

U0078 Chevrolet 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 Chevrolet 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 15,490

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 Chevrolet 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 Chevrolet - Control Module Communication Low Speed CAN Bus Off - AutoCodes.com — U0078 Chevrolet Code - Control Module Communication Low Speed CAN Bus Off

What does this mean?

What are the Possible Causes of the DTC U0078 Chevrolet?

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 Chevrolet?

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 Chevrolet 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 Chevrolet code?

Need more information on how to fix the U0078 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0078 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

U0078 2014 Chevrolet Silverado — Control Module Communication Low Speed CAN Bus Off
U0078 2015 Chevrolet Silverado — Control Module Communication Low Speed CAN Bus Off
U0078 2016 Chevrolet Silverado — Control Module Communication Low Speed CAN Bus Off
U0078 2017 Chevrolet Silverado — Control Module Communication Low Speed CAN Bus Off
U0078 2018 Chevrolet Silverado — Control Module Communication Low Speed CAN Bus Off

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 Chevrolet Code

1. What are the common symptoms of OBDII code U0078 in a Chevrolet vehicle?

- Common symptoms include intermittent or complete loss of communication with various control modules, dashboard warning lights illuminating, and issues with vehicle performance.

2. What could cause the U0078 code to appear in a Chevrolet, indicating Control Module Communication Low Speed CAN Bus Off?

- The code may be triggered by a faulty control module, damaged wiring or connectors, a loose connection, or a problem with the CAN bus network.

3. How can I diagnose the U0078 code in my Chevrolet?

- Diagnosing the U0078 code typically involves using a professional OBDII scanner to check for communication errors between control modules and inspecting the wiring and connectors for any visible damage.

4. What are some repair tips for fixing the U0078 code in a Chevrolet?

- Repair tips include checking and repairing any damaged wiring or connectors, ensuring all connections are secure, resetting the fault codes, and retesting the system for proper communication.

5. Is it safe to continue driving my Chevrolet with the U0078 code present?

- It is not recommended to drive the vehicle with the U0078 code present, as it can lead to further electrical issues and potentially affect the vehicle's performance and safety systems.

6. Can a DIY enthusiast fix the U0078 code in a Chevrolet, or is professional help necessary?

- While some simple checks and repairs can be done by DIY enthusiasts, diagnosing and fixing the root cause of the U0078 code may require professional expertise and specialized equipment.

7. How much does it typically cost to repair the U0078 code in a Chevrolet?

- The cost of repairing the U0078 code can vary depending on the underlying issue and whether professional help is needed. Costs may include parts replacement, labor fees, and diagnostic charges.

8. Are there any preventive measures to avoid the U0078 code in a Chevrolet?

- Regular vehicle maintenance, checking for loose connections or damaged wiring during inspections, and addressing any warning lights promptly can help prevent the U0078 code from appearing.

9. Can extreme weather conditions or environmental factors contribute to the U0078 code in a Chevrolet?

- Yes, extreme weather conditions, moisture, or exposure to harsh environments can potentially damage wiring or connectors, leading to communication issues and triggering the U0078 code.

10. How long does it typically take to repair the U0078 code in a Chevrolet?

- The repair time for the U0078 code can vary depending on the complexity of the issue and the availability of parts. Simple fixes may take a few hours, while more extensive repairs could take longer.