Quick Answer
B1640 means: B1640 indicates a communication error with the body control module.
Can I drive with B1640? Immediate attention is recommended to prevent further electrical issues.
Common Questions
What does B1640 mean and how does it affect my car?
The B1640 code indicates a problem with the communication between your car's body control module and other systems. This can affect various electrical functions such as locking doors, operating windows, and starting the vehicle. If ignored, it may lead to more severe issues affecting your vehicle's reliability.
What are the most common causes of B1640 and how much does it cost to fix?
Common causes include faulty wiring (about 60% of cases) and a malfunctioning BCM (25%). Repair costs can range from $150 for wiring issues to $800 for BCM replacement, depending on the severity of the problem.
Can I drive my car with B1640 or should I stop immediately?
While you can drive your vehicle, it is advised to seek repairs as soon as possible. Continued use may lead to more complicated electrical issues, which could compromise safe driving.
How can I diagnose B1640 myself using GeekOBD APP?
To diagnose B1640, connect the GeekOBD APP to your vehicle's OBD2 port. Run a full system scan to retrieve codes and freeze-frame data. This will help you identify any other related issues and understand the context of the fault.
What vehicles are most commonly affected by B1640?
Vehicles from Ford and GMC, particularly models from 2005 to 2020, frequently experience the B1640 code. Keep an eye on recalls or technical service bulletins related to these models for additional guidance.
How can I prevent B1640 from happening again?
Regular maintenance checks on your vehicle's electrical system can help prevent the B1640 code from occurring. Inspect wiring and connectors for wear, keep connections clean, and avoid after-market modifications that could interfere with the BCM.
What is B1640?
The B1640 diagnostic trouble code (DTC) indicates a communication issue between the body control module (BCM) and other vehicle systems. This code is common in various models from Ford and GMC, particularly in vehicles manufactured between 2005 and 2020. When your car's BCM fails to communicate effectively, it can lead to various electrical problems, including malfunctioning lights, power windows, and locks. The BCM is responsible for managing several electronic components in your vehicle, and when it doesn't work correctly, you may experience symptoms like a non-functional key fob, dashboard warning lights, or even issues with the vehicle starting. In some cases, the problem can stem from faulty wiring, corroded connectors, or a failing BCM. Ignoring this code can lead to more severe electrical issues over time, affecting vehicle safety and reliability. Therefore, it is crucial to address the B1640 code promptly to avoid more extensive repairs and ensure your vehicle operates as intended.
System: B - Body (Airbags, Lighting, Security, Climate Control)
Symptoms
Common symptoms when B1640 is present:
- The dashboard warning lights remain illuminated, indicating potential electrical system faults.
- Power windows and locks may not respond, causing inconvenience for the driver.
- There may be intermittent issues with the vehicle's starting system, leading to unexpected no-start situations.
- The vehicle's key fob may become unresponsive, preventing remote locking or unlocking.
- Erratic behavior of interior lights, such as flickering or remaining on when the vehicle is off.
Possible Causes
Most common causes of B1640 (ordered by frequency):
- The most common cause of the B1640 code is faulty wiring or connectors, which accounts for approximately 60% of cases. This can occur due to wear and tear or exposure to moisture.
- A malfunctioning body control module itself is the second most common cause, typically resulting from internal circuit failures or software issues, occurring in about 25% of cases.
- Corrosion at the BCM connectors can lead to communication failures. Regular inspections and cleaning can help prevent this issue.
- Less commonly, issues with the vehicle's battery or alternator, which affect overall electrical performance, can trigger the B1640 code.
- In rare cases, after-market modifications or installations may interfere with the BCM's operation, leading to potential communication errors.
B1640 Repair Costs
Cost Breakdown by Repair Type
Wiring repairs
Repairing or replacing damaged wiring and connectors associated with the BCM.
- Total: $150 - $400
- Success rate: 85%
BCM replacement
Replacing a faulty body control module with a new or refurbished unit.
- Total: $300 - $800
- Success rate: 90%
Cleaning connectors
Cleaning and resealing corroded connectors to restore communication.
- Total: $50 - $150
- Success rate: 70%
Money-Saving Tips for B1640
- 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 B1640 Diagnosis Process
Follow these systematic steps to accurately diagnose B1640. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze-frame data to understand the fault context
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test suspected components, including the BCM and wiring harness (20-30 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and ensure no codes reappear (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: BCM Communication Issue in a 2015 Ford F-150
Vehicle: 2015 Ford F-150, 75,000 miles
Problem: Customer reported that the power windows and door locks were intermittently malfunctioning.
Diagnosis: After scanning with the GeekOBD APP, the B1640 code was identified, alongside several other codes related to electronic systems.
Solution: A thorough inspection revealed corroded connectors at the BCM. Cleaning and resealing the connectors resolved the issue.
Cost: $120 for cleaning and inspection.
Result: The window and lock functions were restored, and no codes reappeared during follow-up.
Case Study 2: BCM Replacement in a 2018 GMC Sierra
Vehicle: 2018 GMC Sierra, 50,000 miles
Problem: Customer experienced issues with the vehicle starting and dashboard lights malfunctioning.
Diagnosis: The GeekOBD APP scan indicated a B1640 code, and further testing confirmed a faulty BCM.
Solution: The BCM was replaced with a new unit, and the system was reprogrammed.
Cost: $600 for parts and labor.
Result: All electrical functions were restored, and the customer reported satisfaction with the repairs.