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

Quick Answer

The U0077 code on a 2014 GMC Sierra indicates a problem with the Control Module Communication Chassis Expansion CAN Bus. Common causes include Faulty control module on the chassis expansion CAN bus, Corrosion or damage to the wiring harness connected to the control modules, Loose or poor connections between control modules. 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 Faulty control module on the chassis expansion CAN bus, Corrosion or damage to the wiring harness connected to the control modules, Loose or poor connections between control modules.
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
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Code U0077 2014 GMC Sierra Description

The U0077 code on a 2014 GMC Sierra indicates a problem with the Control Module Communication Chassis Expansion CAN Bus. The Controller Area Network (CAN) bus is a communication system that allows various modules in the vehicle to communicate with each other. In this case, the chassis expansion CAN bus is responsible for connecting modules related to the chassis control systems, such as the ABS, traction control, and stability control systems.

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

Common Causes of U0077 2014 GMC Sierra

  1. Faulty control module on the chassis expansion CAN bus.
  2. Corrosion or damage to the wiring harness connected to the control modules.
  3. Loose or poor connections between control modules.
  4. Software issues or programming errors within the control modules.
  5. Electrical interference or signal disruption within the CAN bus system.

Symptoms of U0077 2014 GMC Sierra

  1. Malfunction indicator light (MIL) or check engine light illuminated on the dashboard.
  2. ABS warning light or traction control warning light may be illuminated.
  3. Loss of traction control or stability control functionality.
  4. Erratic behavior of the ABS system, such as pulsating brakes or non-responsive braking.
  5. Reduced overall handling and stability while driving.

How to Fix U0077 2014 GMC Sierra

  1. Diagnose the specific control module or wiring issue causing the communication error using a diagnostic scanner.
  2. Inspect the wiring harness for any signs of damage, corrosion, or loose connections and repair as necessary.
  3. Check and update the software in the affected control modules to address any programming errors.
  4. Clear the trouble codes from the vehicle's computer system and retest to ensure the issue has been resolved.
  5. If the problem persists, replace the faulty control module or repair any other underlying electrical issues causing the communication error.

Cost to Fix U0077 2014 GMC Sierra

The typical repair costs for addressing a U0077 code on a 2014 GMC Sierra can range from $200 to $600, depending on the specific cause of the issue and the labor rates at the repair shop. This estimate includes the cost of parts such as a new control module or wiring harness, as well as labor for diagnosis and repair. It's important to note that actual repair costs can vary based on location, vehicle make and model, and the extent of the necessary repairs. It's recommended to consult with a trusted mechanic or auto repair shop for a more accurate estimate based on your specific situation.

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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.

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