Engine-Codes.com
Engine-Codes – GMC – U0077 GMC

U0077 GMC Code - Control Module Communication Chassis Expansion CAN Bus

Quick Answer

The U0077 GMC code indicates a communication error between control modules in the vehicle's chassis expansion CAN (Controller Area Network) bus. Common causes include Faulty control module in the chassis expansion CAN bus, Wiring harness issues, such as loose connections or damaged wires, Software glitches or programming errors. 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 GMC indicates Control Module Communication Chassis Expansion CAN Bus.
Common causes
Common causes include Faulty control module in the chassis expansion CAN bus, Wiring harness issues, such as loose connections or damaged wires, Software glitches or programming errors.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 07, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code U0077 GMC Description

The U0077 GMC code indicates a communication error between control modules in the vehicle's chassis expansion CAN (Controller Area Network) bus. The CAN bus is a network that allows different electronic control modules within the vehicle to communicate with each other. When this communication is disrupted or lost, it can lead to various issues with the vehicle's performance.

OBDII Code U0077 GMC - Control Module Communication Chassis Expansion CAN Bus
U0077 GMC Code - Control Module Communication Chassis Expansion CAN Bus

Common Causes of U0077 GMC

  1. Faulty control module in the chassis expansion CAN bus.
  2. Wiring harness issues, such as loose connections or damaged wires.
  3. Software glitches or programming errors.
  4. Electrical interference from aftermarket accessories or modifications.
  5. Water or corrosion damage to the control module connectors.

Symptoms of U0077 GMC

  1. ABS warning light illuminated on the dashboard.
  2. Traction control or stability control system malfunctions.
  3. Loss of power steering assistance.
  4. Erratic behavior of the vehicle's braking system.
  5. Unexpected activation of safety systems, such as the airbag.

How to Fix U0077 GMC

  1. Begin by using a diagnostic scanner to retrieve the specific codes and information related to the U0077 code.
  2. Inspect the wiring harness for any visible damage, corrosion, or loose connections. Repair or replace any damaged wires.
  3. Check the control modules in the chassis expansion CAN bus for faults or malfunctions. Replace any faulty modules as needed.
  4. Perform a software update or reprogramming of the control modules to address any glitches or programming errors.
  5. Clear the codes from the vehicle's system and perform a test drive to ensure that the issue has been resolved.

Cost to Fix U0077 GMC

The typical repair costs for addressing the U0077 GMC code can vary depending on the specific cause of the issue and the extent of the repairs needed. On average, the cost for parts and labor to diagnose and repair this issue can range from $200 to $500. However, it's essential to note that the actual costs may be higher or lower based on factors such as the location of the repair shop, the vehicle's make and model, and the complexity of the repair process. It's recommended to consult with a professional mechanic or auto repair shop for a more accurate estimate tailored to your specific situation.

Need more information about the U0077 GMC code?

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

Need Help with the Code?

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

Information for Specific GMC Models

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 GMC Code

1. What are the common symptoms of OBDII code U0077 GMC?

- Common symptoms include the illumination of the Check Engine Light (CEL), issues with the vehicle's stability control system, and intermittent or complete loss of communication with various control modules.

2. What are the possible causes of OBDII code U0077 GMC?

- Possible causes include faulty chassis control module, damaged wiring or connectors in the CAN bus network, software issues, or a malfunctioning electronic control unit (ECU).

3. How can I diagnose OBDII code U0077 GMC?

- Diagnosis typically involves using a diagnostic scan tool to retrieve the code, checking for any other related codes, inspecting the CAN bus network for faults, and testing the communication between control modules.

4. Can OBDII code U0077 GMC be fixed by resetting the ECU?

- Resetting the ECU may temporarily clear the code, but it will reappear if the underlying issue causing the communication error is not resolved. It's important to diagnose and address the root cause of the problem.

5. What are some repair tips for fixing OBDII code U0077 GMC?

- Repair tips may include inspecting and repairing any damaged wiring or connectors in the CAN bus network, updating software if available, replacing faulty control modules, and ensuring proper communication between modules.

6. Is it safe to continue driving with OBDII code U0077 GMC present?

- While the vehicle may still be operable with this code, it's recommended to address the issue promptly to prevent potential safety hazards and further damage to the vehicle's control systems.

7. Can a DIY enthusiast fix OBDII code U0077 GMC at home?

- Depending on the root cause, some DIY enthusiasts with the necessary tools and knowledge may be able to address the issue themselves. However, complex electrical issues may require professional diagnosis and repair.

8. How much does it typically cost to repair OBDII code U0077 GMC at a mechanic or dealership?

- Repair costs can vary depending on the exact cause of the issue, labor rates, and the need for replacement parts. It's advisable to obtain estimates from different mechanics or dealerships before proceeding with the repair.

9. Are there any recalls or technical service bulletins related to OBDII code U0077 GMC?

- It's recommended to check with the vehicle manufacturer or authorized service centers for any recalls or technical service bulletins related to this specific OBDII code, as they may provide valuable information and potential solutions.

10. How can I prevent OBDII code U0077 GMC from recurring in the future?

- To prevent the code from recurring, regular maintenance, timely software updates, and addressing any underlying electrical issues promptly can help maintain the integrity of the vehicle's communication network and control modules.

Discuss the causes and fixes for U0077 GMC OBDII Code

Submit a New Comment

Code U0077 GMC comments

No comments found for this page.