Quick Answer
U0851 means: U0851 indicates a communication error within the vehicle's network.
Can I drive with U0851? Immediate attention is advised to avoid safety risks and further damage.
Common Questions
What does U0851 mean and how does it affect my car?
The U0851 code signifies a communication fault within your vehicle's network. This can lead to issues such as malfunctioning safety systems, reduced performance, and warning lights on your dashboard. It's crucial to address this code swiftly to ensure your vehicle operates safely and effectively.
What are the most common causes of U0851 and how much does it cost to fix?
Common causes include faulty wiring (40% likelihood), defective modules (30%), and software issues (20%). Repair costs can range from $150 to $1,200 depending on the issue, with wiring repairs being the most affordable.
Can I drive my car with U0851 or should I stop immediately?
It's recommended to stop driving if you see the U0851 code. Ignoring it can lead to safety issues and further damage to your vehicle's systems.
How can I diagnose U0851 myself using GeekOBD APP?
To diagnose U0851 using GeekOBD APP, connect it to your vehicle, run a scan to retrieve codes, and check the freeze frame data for context. This will help you understand the issue better before seeking professional help.
What vehicles are most commonly affected by U0851?
Common vehicles experiencing U0851 include the 2015-2020 Ford F-150, Chevrolet Silverado, and GMC Sierra. Owners of these models should be vigilant about communication-related issues.
How can I prevent U0851 from happening again?
Regular maintenance, including inspecting wiring and connectors, updating software, and avoiding aftermarket modifications, can help prevent the recurrence of U0851.
What is U0851?
The Diagnostic Trouble Code (DTC) U0851 indicates a communication error in the vehicle's data network. This code typically means that one or more modules in your vehicle are unable to communicate effectively with the others, which can lead to various issues. This situation is common in models like the 2015-2020 Ford F-150 and Chevrolet Silverado. When modules fail to communicate, it can trigger warning lights, impact performance, and lead to critical failures in safety systems. For example, if the Anti-lock Braking System (ABS) module is unable to relay information, it can affect brake performance, compromising safety. Additionally, you may experience electrical gremlins such as erratic behavior from dashboard lights, non-functioning features, or even stalling in some cases. Understanding this code is crucial because ignoring it may lead to more severe issues like complete module failure or additional DTCs appearing in the future. Therefore, addressing U0851 promptly is essential for maintaining your vehicle's health and safety.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0851 is present:
- The Check Engine Light stays on constantly, indicating a persistent communication issue that needs immediate attention.
- You may experience erratic behavior of dashboard indicators, such as warning lights flickering or non-responsive controls, leading to confusion while driving.
- Fuel economy decreases by 15-20% as the vehicle’s systems fail to operate efficiently due to communication breakdowns.
- Inconsistent engine performance, such as stalling or hesitation during acceleration, making the vehicle unpredictable.
- Loss of functionality in safety features, such as traction control or ABS, potentially compromising your safety on the road.
Possible Causes
Most common causes of U0851 (ordered by frequency):
- Faulty wiring or connectors - 40% likelihood: Damaged or corroded connections can hinder communication between modules.
- Defective modules - 30% likelihood: One or more electronic control modules may be malfunctioning, leading to a communication failure.
- Software glitches - 20% likelihood: Outdated or corrupt software in the vehicle’s modules can disrupt normal operations.
- Interference from aftermarket accessories - 5% likelihood: Improperly installed aftermarket devices can create signal interference.
- Less common but serious cause - 5% likelihood: Issues in the vehicle's main harness can affect the entire network.
U0851 Repair Costs
Cost Breakdown by Repair Type
Wiring and Connector Repair
Repair or replace damaged wiring and connectors to restore communication.
- Total: $150 - $400
- Success rate: 85%
Module Replacement
Replace defective control modules that are failing to communicate.
- Total: $200 - $1,200
- Success rate: 90%
Money-Saving Tips for U0851
- 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 U0851 Diagnosis Process
Follow these systematic steps to accurately diagnose U0851. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes).
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test suspected components (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test suspected components (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes).
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: 2018 Ford F-150 Communication Issue
Vehicle: 2018 Ford F-150, 45,000 miles
Problem: Customer reported erratic dashboard lights and decreased fuel efficiency.
Diagnosis: After scanning for DTCs, U0851 was retrieved. A visual inspection revealed corroded connectors.
Solution: Replaced corroded connectors and performed a software update.
Cost: $250
Result: After repairs, all systems functioned correctly, and the fuel efficiency improved.
Case Study 2: 2019 Chevrolet Silverado Module Replacement
Vehicle: 2019 Chevrolet Silverado, 30,000 miles
Problem: Check Engine Light was on with multiple warning indicators flickering.
Diagnosis: Scanned and confirmed U0851; module testing indicated a defective ABS module.
Solution: Replaced the ABS module and cleared the codes.
Cost: $800
Result: Post-repair, the vehicle showed no further issues, and the warning lights remained off.