U0077 GMC 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 GMC 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.
Code U0077 GMC Description
What are the Possible Causes of the DTC U0077 GMC?
- 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 GMC?
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 GMC 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.
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Information for Specific GMC Models
- U0077 2014 GMC Sierra — Control Module Communication Chassis Expansion CAN Bus
- U0077 2015 GMC Sierra — Control Module Communication Chassis Expansion CAN Bus
- U0077 2016 GMC Sierra — Control Module Communication Chassis Expansion CAN Bus
- U0077 2017 GMC Sierra — Control Module Communication Chassis Expansion CAN Bus
- U0077 2018 GMC Sierra — Control Module Communication Chassis Expansion CAN Bus
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.
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