AutoCodes – Chevrolet – U0077 Chevrolet

U0077 Chevrolet 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 Chevrolet 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 21,915

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 Chevrolet 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 Chevrolet - Control Module Communication Chassis Expansion CAN Bus - AutoCodes.com — U0077 Chevrolet Code - Control Module Communication Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U0077 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 U0077 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 U0077 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 U0077 Chevrolet code?

Need more information on how to fix the U0077 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0077 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

U0077 2014 Chevrolet Silverado — Control Module Communication Chassis Expansion CAN Bus
U0077 2015 Chevrolet Silverado — Control Module Communication Chassis Expansion CAN Bus
U0077 2016 Chevrolet Silverado — Control Module Communication Chassis Expansion CAN Bus
U0077 2017 Chevrolet Silverado — Control Module Communication Chassis Expansion CAN Bus
U0077 2018 Chevrolet Silverado — Control Module Communication Chassis Expansion CAN Bus

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 Chevrolet Code

1. What are the common symptoms of OBDII code U0077 in a Chevrolet related to Control Module Communication Chassis Expansion CAN Bus?

- Common symptoms include issues with the vehicle's stability control system, ABS system, and traction control system. Drivers may experience warning lights on the dashboard and potential loss of these safety features.

2. What are the possible causes of OBDII code U0077 in a Chevrolet?

- The code U0077 typically indicates a communication fault between control modules in the chassis expansion CAN bus system. Common causes include wiring issues, faulty control modules, or a malfunctioning CAN bus network.

3. How can I diagnose a U0077 code in my Chevrolet?

- Diagnosing a U0077 code requires using a diagnostic scanner to retrieve the trouble codes and pinpoint the affected control modules. It is essential to check the wiring connections, inspect for physical damage, and perform communication tests between modules.

4. Can a U0077 code be cleared/reset in a Chevrolet, and will it resolve the issue?

- Clearing the U0077 trouble code may temporarily turn off the warning lights, but it will not fix the underlying communication problem. It is crucial to address the root cause of the code by repairing any wiring faults, replacing faulty modules, or fixing CAN bus network issues.

5. Are there any simple repair tips for fixing a U0077 code in a Chevrolet?

- Simple repair tips for resolving a U0077 code include checking and securing all wiring connections, ensuring proper grounding, and inspecting for physical damage or corrosion. Replacing damaged wires or connectors may help restore communication between modules.

6. Is it safe to drive a Chevrolet with a U0077 code present?

- It is not recommended to drive a vehicle with an active U0077 code, as it can affect the proper functioning of critical safety systems like stability control and ABS. Continuing to drive with this code may compromise the vehicle's overall safety.

7. How much does it typically cost to repair a U0077 code in a Chevrolet?

- The cost of repairing a U0077 code can vary depending on the root cause of the communication issue. Expenses may include diagnostic fees, replacement parts, labor costs, and any necessary reprogramming of control modules. It is advisable to consult a professional mechanic for an accurate estimate.

8. Can a DIY enthusiast fix a U0077 code in a Chevrolet, or is professional help necessary?

- While some basic troubleshooting steps can be performed by a DIY enthusiast, resolving a U0077 code often requires specialized diagnostic equipment and expertise. Due to the complexity of the CAN bus system, professional help may be necessary for an effective repair.

9. How long does it take to repair a U0077 code in a Chevrolet?

- The repair time for a U0077 code can vary based on the extent of the communication issue and the specific repairs needed. Simple fixes like reconnecting loose wires may take a short time, while more complex issues such as module replacements or network repairs could require several hours or more.

10. What steps should be taken if a U0077 code keeps recurring in a Chevrolet after repairs?

- If a U0077 code keeps coming back after repairs, it is essential to recheck all connections, verify the integrity of the CAN bus network, and ensure that the replacement modules are functioning correctly. Consulting with a professional technician may be necessary to address persistent issues.