AutoCodes – Chevrolet – U0078 2018 Chevrolet Silverado

U0078 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 704

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - Control Module Communication Low Speed CAN Bus Off - AutoCodes.com — U0078 2018 Chevrolet Silverado Code - Control Module Communication Low Speed CAN Bus Off

What does this mean?

What are the Possible Causes of the DTC U0078 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the U0078 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado Code

1. What does OBDII code U0078 mean on a 2018 Chevrolet Silverado?

Code U0078 indicates a communication issue on the low-speed CAN (Controller Area Network) bus, where one or more control modules are unable to communicate properly.

2. What are the common symptoms of code U0078 on a 2018 Chevrolet Silverado?

Symptoms may include warning lights on the dashboard, intermittent electrical issues, unresponsive systems like the infotainment or HVAC, or failure of certain features to work.

3. What causes code U0078 to appear?

Common causes include a faulty control module, damaged or corroded wiring, loose or damaged CAN bus connectors, or electrical interference on the low-speed CAN bus.

4. Can a dead battery trigger code U0078 on a Chevrolet Silverado?

Yes, a weak or dead battery can cause voltage irregularities, potentially disrupting communication on the low-speed CAN bus and triggering code U0078.

5. How can I diagnose code U0078 on my 2018 Silverado?

Start by checking for damaged wiring, loose connectors, or corrosion on the CAN bus network. Use a scan tool to identify the specific module that is not communicating and test the network's continuity and resistance.

6. Is it safe to drive with code U0078 on my Silverado?

It depends on the severity of the communication issue. If critical systems like braking or steering are affected, driving may not be safe. Itâ€™s best to address the issue promptly.

7. How do I fix code U0078 on a Chevrolet Silverado?

Repairs may include cleaning or replacing corroded connectors, repairing damaged wiring, reprogramming or replacing a faulty control module, or addressing any related electrical issues.

8. Can a software update fix code U0078?

In some cases, a software update to the affected control module may resolve communication issues, but this depends on the root cause of the code.

9. What tools are needed to troubleshoot code U0078?

Youâ€™ll need a professional-grade OBDII scan tool capable of reading CAN bus communication, a multimeter to test wiring and continuity, and possibly an oscilloscope for advanced diagnostics.

10. How much does it cost to repair code U0078 on a 2018 Chevrolet Silverado?

Repair costs vary depending on the issue. Minor fixes like cleaning connectors may cost little, while replacing a control module or extensive wiring repairs can cost several hundred dollars or more.