U0812 - Understanding Communication Issue in 2015-2020 Chevrolet and GMC Vehicles

Quick Answer

U0812 means: U0812 indicates a communication issue between control modules in your vehicle.

Fix: Check and replace faulty components Cost: $300 - $600 Time: 90-180 minutes

Can I drive with U0812? Immediate attention is recommended to prevent safety issues.

Common Questions

What does U0812 mean and how does it affect my car?

The U0812 code indicates a communication failure between the vehicle's control modules. This can lead to issues with electronic systems, affecting everything from lights and windows to safety features. If ignored, it may result in more significant problems or safety hazards.

What are the most common causes of U0812 and how much does it cost to fix?

Common causes of U0812 include a faulty body control module, damaged wiring, or a weak battery. Repair costs can range from $150 for wiring repairs to $600 for BCM replacement, depending on the specific issue.

Can I drive my car with U0812 or should I stop immediately?

While you might be able to drive your car with the U0812 code, it's advisable to avoid doing so until the issue is resolved. Ignoring this code can lead to safety system failures, which could pose a risk during driving.

How can I diagnose U0812 myself using GeekOBD APP?

To diagnose U0812 with the GeekOBD APP, connect the device to your vehicle's OBD-II port, scan for trouble codes, and review freeze frame data. Look for patterns or additional codes that may point to the underlying issue and follow the diagnostic steps outlined.

What vehicles are most commonly affected by U0812?

U0812 is frequently seen in 2015-2020 Chevrolet and GMC models, including the Silverado, Sierra, and Tahoe. It's essential to check for any manufacturer recalls or technical service bulletins (TSBs) related to this code.

How can I prevent U0812 from happening again?

Regular vehicle maintenance, checking wiring and connections for wear, and ensuring your battery is in good condition can help prevent U0812 from recurring. Also, be cautious when installing aftermarket accessories that could interfere with the vehicle's electronics.

What is U0812?

The diagnostic trouble code (DTC) U0812 indicates a communication issue between control modules in the vehicle, specifically related to the vehicle's communication network. This code is most commonly found in 2015-2020 Chevrolet and GMC models, including trucks like the Silverado and Sierra. When U0812 is triggered, it means that one of the modules, often the body control module (BCM), is not receiving or sending information properly to other modules. This issue can lead to a variety of performance problems, such as malfunctioning lights, failure of safety systems like airbags, or issues with electronic stability control. In practical terms, if you're experiencing this code, it’s essential to address it promptly, as ignoring it can lead to further complications or even safety hazards. A vehicle equipped with advanced features like lane assist or adaptive cruise control may not function correctly if communication between modules is disrupted. Regular diagnostics using tools like the GeekOBD APP can help you identify the root cause, whether it's a wiring issue, a failed module, or a software glitch.

System: U - Network (Communication, CAN Bus)

Symptoms

Common symptoms when U0812 is present:

  • The check engine light or service engine soon light is illuminated consistently, indicating a potential fault.
  • You may notice erratic behavior in electronic systems, such as dashboard warning lights flickering or malfunctioning.
  • Vehicle features like power windows, door locks, or interior lights may function intermittently or not at all, causing frustration.
  • Unexpected system resets can occur, where the radio or infotainment system turns off and on without user input.
  • In extreme cases, vehicle safety features like traction control or airbags might fail to operate correctly, posing a safety risk.

Possible Causes

Most common causes of U0812 (ordered by frequency):

  1. The most common cause of U0812 is a faulty body control module (BCM), which is responsible for managing communication between various electronic components. This issue occurs in about 60% of cases and can arise from internal failures or software glitches.
  2. Another frequent cause could be damaged wiring or corroded connectors, leading to poor communication. This accounts for roughly 25% of U0812 occurrences and is often related to exposure to moisture or road debris.
  3. A weak or failing battery can also trigger U0812, as low voltage can disrupt communication between modules. Regular battery maintenance and ensuring proper connections can help prevent this issue.
  4. Less commonly, a malfunctioning or incompatible aftermarket accessory, such as an audio system or alarm, can interfere with the vehicle's network, causing U0812 to appear.
  5. In rare cases, software bugs in the vehicle's control modules require a software update to resolve communication issues.

U0812 Repair Costs

Cost Breakdown by Repair Type

Body Control Module Replacement

Replacing the faulty BCM with a new or refurbished unit, including programming to match the vehicle's configuration.

  • Total: $300 - $600
  • Success rate: 85%
Wiring Repair

Repairing or replacing damaged wiring and connectors to restore proper communication between modules.

  • Total: $150 - $300
  • Success rate: 75%
Money-Saving Tips for U0812
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional U0812 Diagnosis Process

Follow these systematic steps to accurately diagnose U0812. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Perform an initial visual inspection to check for damaged wiring, loose connections, or signs of corrosion around the BCM and related connectors (5-10 minutes)

Step 1: Perform an initial visual inspection to check for damaged wiring, loose connections, or signs of corrosion around the BCM and related connectors (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: Use the GeekOBD APP to scan for all trouble codes and retrieve freeze frame data to understand the context of the fault (10-15 minutes)

Step 2: Use the GeekOBD APP to scan for all trouble codes and retrieve freeze frame data to understand the context of the fault (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Test the BCM and other suspected components using a multimeter or specific diagnostic tools to ensure they are functioning correctly (20-30 minutes)

Step 3: Test the BCM and other suspected components using a multimeter or specific diagnostic tools to ensure they are functioning correctly (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: Conduct a system function test to verify proper operation of the electronic systems after repairs and clear any codes present (10-15 minutes)

Step 4: Conduct a system function test to verify proper operation of the electronic systems after repairs and clear any codes present (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Complete a road test under various driving conditions to confirm the repair's success and ensure no further issues arise (15-20 minutes)

Step 5: Complete a road test under various driving conditions to confirm the repair's success and ensure no further issues arise (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Body Control Module Replacement in a 2018 Chevrolet Silverado

Vehicle: 2018 Chevrolet Silverado 1500, 45,000 miles

Problem: Customer reported intermittent functioning of power windows and dashboard lights.

Diagnosis: Initial diagnostics revealed U0812 and confirmed issues with the BCM through wiring tests.

Solution: Replaced the faulty BCM and reprogrammed it to the vehicle's specifications.

Cost: $550 (including parts and labor)

Result: All systems operated normally post-repair, and customer reported no further issues.

Case Study 2: Wiring Repair in a 2016 GMC Sierra

Vehicle: 2016 GMC Sierra 2500HD, 60,000 miles

Problem: Vehicle experienced sporadic electrical system failures and U0812 code.

Diagnosis: Found corroded connectors and damaged wiring harness near the BCM.

Solution: Repaired wiring and replaced corroded connectors to restore communication.

Cost: $200 (specific cost breakdown included labor for diagnostics and repair)

Result: Resolved the U0812 code and restored proper functionality to electronic systems.

Diagnose U0812

Use GeekOBD APP for professional diagnosis!

  • Real-time data monitoring
  • Advanced diagnostic features
  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: U0812
System: Network (Communication, CAN Bus)
Severity: HIGH
Category: Network Codes