AutoCodes – Buick – U0077 Buick

U0077 Buick 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 Buick 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 4,344

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

What does this mean?

What are the Possible Causes of the DTC U0077 Buick?

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 Buick?

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 Buick 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 Buick code?

Need more information on how to fix the U0077 Buick 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 Buick Code

1. What does the OBDII code U0077 for Buick indicate?

The U0077 code signifies a communication problem in the Chassis Expansion CAN Bus network within the vehicle's control modules.

2. What are common symptoms of the U0077 code in a Buick?

Common symptoms include issues with the ABS system, traction control system, stability control system, or other chassis-related functions. The vehicle may also experience a loss of communication with certain control modules.

3. What are possible causes of the U0077 code in a Buick?

Potential causes of the U0077 code include damaged wiring or connectors in the Chassis Expansion CAN Bus network, faulty control modules, software glitches, or issues with the vehicle's battery or electrical system.

4. How can I diagnose the U0077 code in my Buick?

Diagnosing the U0077 code typically involves using a professional OBDII scanner to retrieve the specific details of the code. A thorough inspection of the Chassis Expansion CAN Bus network, wiring, connectors, and control modules may be necessary to pinpoint the exact cause.

5. Can I still drive my Buick with the U0077 code present?

It is generally not recommended to drive your Buick with the U0077 code active, as it can affect critical safety systems like ABS and traction control. It's best to address the issue promptly to ensure the vehicle's proper functionality.

6. How can I repair the U0077 code in my Buick?

Repairing the U0077 code may involve fixing any damaged wiring or connectors in the Chassis Expansion CAN Bus network, replacing faulty control modules, updating software as needed, or addressing any underlying electrical issues.

7. Is the U0077 code a serious problem in a Buick?

While the U0077 code may not always indicate a critical issue, it is essential to address it promptly to prevent potential safety concerns related to the affected chassis control systems.

8. Can a DIY enthusiast fix the U0077 code in a Buick?

Depending on the underlying cause of the U0077 code, some DIY enthusiasts with the necessary tools and knowledge of automotive electrical systems may be able to address the issue. However, for more complex issues, professional assistance may be required.

9. How much does it typically cost to repair the U0077 code in a Buick?

The cost of repairing the U0077 code can vary significantly depending on the specific cause of the issue, the extent of the repairs needed, and whether any parts require replacement. It's advisable to consult with a mechanic for a more accurate estimate.

10. Will resetting the U0077 code make it go away permanently?

Simply resetting the U0077 code may temporarily clear the warning light, but if the underlying issue is not addressed, the code is likely to reappear. It's crucial to diagnose and repair the root cause of the problem to prevent ongoing issues.