AutoCodes – GMC – U0020 2016 GMC Sierra

U0020 2016 GMC Sierra Code - Low Speed CAN Bus

Quick Answer

Devices connected to the General Motors Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include If other codes are present, diagnose other codes first, 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: U0020 2016 GMC Sierra indicates Low Speed CAN Bus.
Common causes: Common causes include If other codes are present, diagnose other codes first, 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 270

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
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U0020 2016 GMC Sierra Description

Devices connected to the General Motors Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages need to be exchanged on the serial data circuits. The messages are also supervised, and some periodic messages are used by the receiver device as an availability indication of the transmitter device. The Diagnostic Trouble Code (DTC) will be set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U0020 2016 GMC Sierra - Low Speed CAN Bus - AutoCodes.com — U0020 2016 GMC Sierra Code - Low Speed CAN Bus

What does this mean?

What are the Possible Causes of the DTC U0020 2016 GMC Sierra?

If other codes are present, diagnose other codes first
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0020 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 does this mean?

Code Tech Notes

Controller Area Network (CAN)

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0020 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 U0020 2016 GMC Sierra code?

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Need Help with the Code?

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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 U0020 2016 GMC Sierra Code

What does the OBDII code U0020 mean for a 2016 GMC Sierra?

The OBDII code U0020 indicates a problem with the Low Speed CAN Bus communication, which can affect various electronic control modules in the vehicle.

What are common symptoms of the U0020 code?

Common symptoms include warning lights on the dashboard, erratic behavior of electronic components, and issues with vehicle functions like power windows or radio.

What could cause the U0020 code to appear?

Potential causes include damaged wiring or connectors in the CAN Bus system, faulty electronic control modules, or issues with the battery or ground connections.

How can I diagnose the U0020 code?

To diagnose the U0020 code, inspect the wiring and connectors for damage, check for other related codes, and use a multimeter to test the voltage and continuity of the CAN Bus lines.

What repairs are typically needed for the U0020 code?

Repairs may involve fixing or replacing damaged wiring or connectors, reprogramming or replacing faulty control modules, or addressing any issues with the vehicle's battery or ground connections.

Can I drive my 2016 GMC Sierra with the U0020 code?

While it may be possible to drive the vehicle, it is not recommended as it can lead to further issues with the vehicle's electronic systems and safety features.

Is the U0020 code serious?

Yes, the U0020 code can be serious as it indicates a communication issue in the vehicle's electronic systems, potentially affecting safety and performance.

How much will it cost to fix the U0020 code?

Repair costs can vary widely depending on the underlying issue, ranging from simple wiring repairs to more expensive replacements of control modules, typically between $100 to $1,000 or more.

Can I clear the U0020 code without fixing the problem?

You can clear the code with a scan tool, but the issue will likely return if the underlying problem is not addressed.

Are there any preventative measures for the U0020 code?

Regularly inspecting the vehicle's wiring and connections, keeping the battery in good condition, and addressing any electrical issues promptly can help prevent the U0020 code from occurring.