Quick Answer
U0870 means: U0870 indicates a loss of communication with the Body Control Module, affecting various electronic systems.
Can I drive with U0870? Immediate attention is recommended to prevent further electrical system failures.
Common Questions
What does U0870 mean and how does it affect my car?
U0870 indicates that your vehicle's Body Control Module is not communicating properly with other modules. This can lead to issues with electrical components like windows, locks, and even starting the vehicle. Addressing this code promptly can prevent further electrical failures and enhance the reliability of your vehicle.
What are the most common causes of U0870 and how much does it cost to fix?
Common causes of U0870 include faulty wiring connections, defective BCMs, and short circuits, with repair costs ranging from $100 for wiring repairs to $800 for BCM replacement. Identifying the specific cause is crucial for accurate repairs.
Can I drive my car with U0870 or should I stop immediately?
It's advisable to avoid driving your vehicle with U0870, as the loss of communication can lead to critical system failures, including starting issues. If you experience symptoms, seek professional diagnostics immediately.
How can I diagnose U0870 myself using GeekOBD APP?
Using the GeekOBD APP, connect your OBD2 scanner to retrieve codes and freeze frame data. Look for any related codes and monitor live data to check the operation of the BCM and associated systems.
What vehicles are most commonly affected by U0870?
U0870 is frequently seen in 2010-2022 Chevrolet Silverado, GMC Sierra, and other GM models. Check for any recalls or Technical Service Bulletins (TSBs) related to the BCM for your vehicle.
How can I prevent U0870 from happening again?
To prevent U0870, ensure regular maintenance checks on electrical systems, inspect wiring for wear and corrosion, and address any electrical anomalies immediately to avoid future communication issues.
What is U0870?
The diagnostic trouble code (DTC) U0870 indicates a communication issue between the vehicle's onboard computer systems, specifically indicating that the Body Control Module (BCM) is unable to transmit or receive data from other modules such as the Engine Control Module (ECM) or Transmission Control Module (TCM). This can lead to various electronic malfunctions affecting critical systems such as lighting, power windows, or even the anti-theft system. The BCM is responsible for controlling many of the vehicle's electrical systems, making U0870 a significant concern. Symptoms can manifest as erratic behavior of electrical components or warning lights on the dashboard. Ignoring this code may lead to further complications, including the inability to start the vehicle or complete failure of electrical systems. It's essential to address this code promptly to ensure the safety and proper functioning of your vehicle. Understanding U0870's implications can help you prevent costly repairs in the future and maintain your vehicle's reliability.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0870 is present:
- Check engine light stays on constantly, indicating communication issues that could affect vehicle performance.
- Power windows or locks fail to operate, leading to inconvenience and potential safety risks.
- Erratic dashboard lights, such as flickering or malfunctioning indicators, suggesting underlying electrical problems.
- Vehicle fails to start due to loss of communication between the BCM and ECM, preventing engine ignition.
- Non-functioning lighting systems, including headlights and interior lights, which can create hazardous driving conditions.
Possible Causes
Most common causes of U0870 (ordered by frequency):
- Faulty wiring connections (40%) - Loose or corroded wiring can disrupt communication pathways between modules.
- Defective Body Control Module (30%) - The BCM itself may be malfunctioning, requiring replacement.
- Short circuits in wiring harness (20%) - Damaged insulation or pinched wires can lead to shorts and communication loss.
- Software issues (5%) - Outdated or corrupted firmware in the BCM may require reprogramming.
- Environmental damage (5%) - Exposure to moisture or extreme temperatures can impact module performance.
U0870 Repair Costs
Cost Breakdown by Repair Type
Wiring Repair
Repairing or replacing damaged wiring and connectors to restore communication.
- Total: $100 - $300
- Success rate: 85%
BCM Replacement
Replacing the faulty Body Control Module with a new one.
- Total: $300 - $800
- Success rate: 90%
Software Reprogramming
Updating or reprogramming the BCM's software to correct communication errors.
- Total: $50 - $150
- Success rate: 75%
Money-Saving Tips for U0870
- 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 U0870 Diagnosis Process
Follow these systematic steps to accurately diagnose U0870. 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: 2015 Chevrolet Silverado BCM Replacement
Vehicle: 2015 Chevrolet Silverado 1500, 75,000 miles
Problem: Customer reported intermittent dashboard warning lights and power window failures.
Diagnosis: After scanning with the GeekOBD APP, U0870 was identified alongside several other codes. A visual inspection revealed corroded wiring to the BCM.
Solution: Replaced the corroded wiring and the BCM, followed by reprogramming the new BCM.
Cost: $600 (parts: $400 BCM, $200 wiring repair)
Result: All systems returned to normal functionality, and the customer reported no further issues.
Case Study 2: 2018 GMC Sierra BCM Software Update
Vehicle: 2018 GMC Sierra 1500, 50,000 miles
Problem: Check engine light was on, and the vehicle exhibited erratic electrical behavior.
Diagnosis: Diagnostic scan revealed U0870 with no visible wiring issues. Further testing showed outdated BCM software.
Solution: Performed software update on the BCM to restore proper communication.
Cost: $100 (software update)
Result: The issue was resolved, and the vehicle's systems functioned correctly post-update.