Quick Answer
U0339 means: U0339 indicates a lost communication with the Body Control Module, affecting various electronic systems in your vehicle.
Can I drive with U0339? Immediate attention is recommended to prevent further electronic malfunctions.
Common Questions
What does U0339 mean and how does it affect my car?
U0339 indicates a lost communication with the Body Control Module, which can affect various electronic functions in your vehicle. If left unresolved, it may lead to more significant electronic failures or safety hazards.
What are the most common causes of U0339 and how much does it cost to fix?
Common causes include a faulty BCM, damaged wiring, or issues with the ECM. Repair costs can range from $100 to $600, depending on whether you need to repair wiring, replace the BCM, or update the ECM.
Can I drive my car with U0339 or should I stop immediately?
While you can technically drive your car, it is not advisable to ignore this code. The malfunctioning electronics could lead to safety issues, such as lights failing or doors unlocking unexpectedly.
How can I diagnose U0339 myself using GeekOBD APP?
Use the GeekOBD APP to scan for DTCs and view freeze frame data to understand the conditions when the fault occurred. Look for other related codes that may provide more context about the U0339.
What vehicles are most commonly affected by U0339?
U0339 is commonly found in models like the 2015-2018 Ford F-150, Chevrolet Silverado, and many other vehicles that rely on a BCM for electronic functions, especially ones made after 2010.
How can I prevent U0339 from happening again?
Regular vehicle maintenance, including checking wiring and connectors for corrosion, keeping the BCM dry, and ensuring software updates are applied, can help prevent future occurrences of U0339.
What is U0339?
The diagnostic trouble code (DTC) U0339 indicates a communication issue between the vehicle's Engine Control Module (ECM) and the Body Control Module (BCM). The BCM is responsible for various electronic functions in the vehicle, such as lighting, windows, and security systems. When the ECM cannot communicate with the BCM, it can lead to several anomalies in vehicle operation, including issues with lighting, door locks, and more. This code can arise due to faulty wiring, a malfunctioning BCM, or issues in the ECM itself. In real-world terms, if your vehicle is throwing this code, you might notice that your lights flicker, your doors might not lock or unlock properly, and certain features may not operate correctly. Ignoring this code could lead to bigger issues down the line, including complete failure of electronic systems, which could result in safety concerns while driving. Overall, it's crucial to address U0339 promptly to ensure your vehicle operates smoothly and safely.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0339 is present:
- Check engine light stays on constantly, indicating a communication failure.
- Interior lights may flicker or not operate at all, affecting driver visibility.
- Power windows may fail to respond to controls, leading to inconvenience.
- Remote key fob may not work, making it difficult to lock or unlock the vehicle.
- Dashboard warnings for various systems may appear, confusing the driver.
Possible Causes
Most common causes of U0339 (ordered by frequency):
- The most common cause of U0339 is a faulty Body Control Module (BCM), occurring in about 60% of cases. BCMs can fail due to internal electronic issues or water intrusion.
- Wiring issues, such as damaged or corroded connectors, represent around 25% of cases. These can disrupt communication between the ECM and BCM.
- Faulty Engine Control Module (ECM) can also trigger this code, though it’s less frequent. Regular software updates and maintenance can help prevent this.
- Less common causes include issues with other control modules affecting the network, which could require advanced diagnostic tools to pinpoint.
- Rarely, a factory recall related to wiring harness issues might lead to this code, so checking for recalls on your vehicle model is advisable.
U0339 Repair Costs
Cost Breakdown by Repair Type
BCM Replacement
Replacing the faulty Body Control Module with a new unit.
- Total: $300 - $600
- Success rate: 90%
Wiring Repair
Repairing or replacing damaged wiring or connectors related to BCM communication.
- Total: $100 - $300
- Success rate: 80%
ECM Update
Updating the Engine Control Module software to ensure compatibility.
- Total: $50 - $150
- Success rate: 75%
Money-Saving Tips for U0339
- 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 U0339 Diagnosis Process
Follow these systematic steps to accurately diagnose U0339. 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, which might indicate communication issues (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion, which might indicate communication issues (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context. Pay attention to any additional codes that may help narrow down the issue (10-15 minutes).
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the BCM and wiring harness for continuity and proper voltage (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the BCM and wiring harness for continuity and proper voltage (20-30 minutes).
Step 4: Step 4: System function test - After repairs, verify the proper operation of all controlled systems and clear codes from the ECM (10-15 minutes)
Step 4: System function test - After repairs, verify the proper operation of all controlled systems and clear codes from the ECM (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm that the issue has been resolved and no new codes appear (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm that the issue has been resolved and no new codes appear (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: Fixed BCM Communication Issue on 2016 Ford F-150
Vehicle: 2016 Ford F-150, 45,000 miles
Problem: Customer reported intermittent power door lock failures and flickering interior lights.
Diagnosis: Performed a visual inspection and found corroded connectors leading to the BCM.
Solution: Replaced the damaged connectors and cleaned the wiring harness.
Cost: $200 (labor and parts included)
Result: All electronic features functioned normally after repair, and no codes reappeared.
Case Study 2: Replaced Faulty BCM on 2017 Chevrolet Silverado
Vehicle: 2017 Chevrolet Silverado, 30,000 miles
Problem: Customer experienced issues with the remote key fob, which would not lock/unlock the doors.
Diagnosis: Scanned the vehicle and confirmed U0339, indicating a BCM failure.
Solution: Replaced the Body Control Module and reprogrammed it to the vehicle.
Cost: $550 (BCM and labor)
Result: After the replacement, the remote function worked flawlessly, and all electronic systems were restored.