AutoCodes – GMC – U0077 2014 GMC Sierra

U0077 2014 GMC Sierra Code - Control Module Communication Chassis Expansion CAN Bus

Quick Answer

The devices connected to the chassis high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. 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: U0077 2014 GMC Sierra indicates Control Module Communication Chassis Expansion CAN Bus.
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 468

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 U0077 2014 GMC Sierra Description

The devices connected to the chassis high speed General Motor 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 when the ignition switch is in any position other than OFF. The chassis high speed GMLAN serial data bus uses terminating resistors that are in parallel with the chassis high speed GMLAN (+) and (-) circuits. The Diagnostic Trouble Code (DTC) sets when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U0077 2014 GMC Sierra - Control Module Communication Chassis Expansion CAN Bus - AutoCodes.com — U0077 2014 GMC Sierra Code - Control Module Communication Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U0077 2014 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 U0077 2014 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 U0077 2014 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 U0077 2014 GMC Sierra code?

Need more information on how to fix the U0077 2014 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 U0077 2014 GMC Sierra Code

What does the OBDII code U0077 mean for a 2014 GMC Sierra?

The U0077 code indicates a communication issue with the Control Module related to the Chassis Expansion CAN Bus, which affects data transmission between modules.

What are the common symptoms of U0077 in a 2014 GMC Sierra?

Common symptoms may include warning lights on the dashboard, loss of communication with certain vehicle systems, and potential issues with features like stability control or traction control.

What could cause the U0077 code to trigger in my GMC Sierra?

Causes may include faulty wiring or connectors in the CAN Bus system, a malfunctioning control module, or issues with the vehicle's electrical system.

Can I drive my 2014 GMC Sierra with the U0077 code?

While you may be able to drive the vehicle, it is not advisable as communication issues can lead to impaired functionality of essential systems, potentially compromising safety.

How can I diagnose the U0077 code?

To diagnose the U0077 code, use an OBD-II scanner to check for related codes, inspect wiring and connectors for damage, and test the affected control modules for proper operation.

What is the typical repair process for U0077?

Repair typically involves inspecting and repairing any damaged wiring or connectors, resetting the control modules, and replacing any faulty control modules if necessary.

Are there any preventative measures to avoid U0077 in the future?

Regular vehicle maintenance, including checking wiring and connectors for wear, can help prevent communication issues. Keeping the vehicle's software updated may also reduce the risk of coding errors.

Will clearing the U0077 code fix the underlying problem?

Clearing the code may temporarily turn off the warning lights, but it will not fix the underlying communication issue. Proper diagnosis and repair are necessary to resolve the problem permanently.

What should I do if I frequently see the U0077 code?

If the U0077 code reappears frequently, it's best to consult a qualified mechanic or technician who can perform a thorough diagnostic to identify and rectify the specific issue.