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Engine-Codes – Generic – U0077

U0077 Code - Control Module Communication Chassis Expansion CAN Bus

Quick Answer

The U0077 code indicates a communication problem between control modules on the chassis expansion CAN bus. Common causes include Faulty control module on the chassis expansion CAN bus, Damaged wiring or connectors in the CAN bus network, Corrosion or poor connections in the communication lines. 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 indicates Control Module Communication Chassis Expansion CAN Bus.
Common causes
Common causes include Faulty control module on the chassis expansion CAN bus, Damaged wiring or connectors in the CAN bus network, Corrosion or poor connections in the communication lines.
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 Aug 18, 2024
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Code U0077 Description

The U0077 code indicates a communication problem between control modules on the chassis expansion CAN bus. The Controller Area Network (CAN) bus is a network that allows various control modules in the vehicle to communicate with each other. In this case, the code specifically relates to communication issues on the chassis expansion CAN bus, which may include modules related to the chassis control, suspension system, or other components. When this communication is disrupted, it can lead to various issues with the vehicle's performance and functionality.

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

Common Causes of U0077

  1. Faulty control module on the chassis expansion CAN bus
  2. Damaged wiring or connectors in the CAN bus network
  3. Corrosion or poor connections in the communication lines
  4. Software issues or programming errors in control modules
  5. Physical damage to the control module or CAN bus components

Symptoms of U0077

  1. Check engine light illuminated
  2. Unresponsive electronic stability control system
  3. ABS system malfunction
  4. Loss of communication with chassis control module
  5. Inconsistent or erratic vehicle behavior

How to Fix U0077

  1. Begin by using a diagnostic scanner to retrieve and record the trouble codes.
  2. Inspect the wiring and connectors in the chassis expansion CAN bus network for any damage or corrosion.
  3. Check the control modules on the network for faults or errors and replace if necessary.
  4. Clear the trouble codes from the vehicle's memory and perform a relearn procedure if required.
  5. Test drive the vehicle to ensure that the issue has been resolved and that all systems are functioning properly.

Cost to Fix U0077

The cost of repairing a U0077 code can vary depending on the specific cause of the issue. In general, parts for replacing a control module or repairing wiring/connectors can range from $100 to $500 or more. Labor costs typically range from $100 to $300, with total repair costs potentially exceeding $500 in some cases. As mentioned earlier, labor rates at auto repair shops can vary, so it's best to check with local shops for more accurate pricing.

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Code U0077 Information for Specific Makes

  • U0077 Buick — Control Module Communication Chassis Expansion CAN Bus
  • U0077 Cadillac — Control Module Communication Chassis Expansion CAN Bus
  • U0077 Chevrolet — Control Module Communication Chassis Expansion CAN Bus
  • U0077 GMC — 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 Code

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

The common symptoms of OBDII code U0077 include issues with communication between various control modules in the vehicle, such as warning lights on the dashboard, erratic behavior of electronic components, and possible difficulty starting the vehicle.

2. What causes OBDII code U0077 to trigger?

OBDII code U0077 is typically triggered by a failure or disruption in communication on the Chassis Expansion CAN Bus, which connects various control modules related to the vehicle's chassis systems.

3. How can I diagnose the cause of OBDII code U0077?

Diagnosing the cause of OBDII code U0077 usually involves using a diagnostic scanner to retrieve the specific fault codes stored in the affected control modules. Additionally, checking the wiring and connections related to the Chassis Expansion CAN Bus is essential.

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

Repairing OBDII code U0077 often involves inspecting and repairing any damaged wiring or connections on the Chassis Expansion CAN Bus. Resetting the fault codes and retesting the system after repairs can help ensure the issue is resolved.

5. Can OBDII code U0077 be fixed without professional help?

While some basic troubleshooting steps can be taken by DIY enthusiasts, fixing OBDII code U0077 may require advanced diagnostic tools and expertise. It is recommended to seek assistance from a professional mechanic for accurate diagnosis and repair.

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

Continuing to drive with OBDII code U0077 present is not recommended, as it can lead to further issues with the vehicle's electronic systems. It is best to address the underlying cause of the code as soon as possible to prevent potential safety hazards.

7. How much does it cost to repair OBDII code U0077?

The cost of repairing OBDII code U0077 can vary depending on the specific cause of the issue, the extent of the damage, and labor rates in your area. It is advisable to obtain quotes from local mechanics or repair shops for an accurate estimate.

8. Can a low battery voltage cause OBDII code U0077 to trigger?

Yes, a low battery voltage or electrical system issues can sometimes lead to the triggering of OBDII code U0077. Ensuring the battery and charging system are in good condition is essential for proper communication between control modules.

9. Will resetting the fault codes make OBDII code U0077 disappear permanently?

Simply resetting the fault codes associated with OBDII code U0077 may temporarily make the warning lights disappear, but if the underlying issue is not addressed, the code is likely to reappear once the system detects the communication problem again.

10. Are there specific vehicle makes and models more prone to OBDII code U0077?

While OBDII code U0077 can potentially occur in any vehicle with a Chassis Expansion CAN Bus, certain makes and models known for electronic system complexities may be more prone to experiencing communication issues leading to this code.

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