C0B21 - Understanding the Diagnostic Trouble Code for 2015-2018 Honda Accord and More

Quick Answer

C0B21 means: DTC C0B21 indicates a malfunction in the lane departure warning system of your vehicle.

Fix: Check and replace faulty components Cost: $150 - $400 Time: 90-180 minutes

Can I drive with C0B21? Immediate attention required to ensure safety and proper vehicle function.

Common Questions

What does C0B21 mean and how does it affect my car?

DTC C0B21 indicates a fault in the lane departure warning system, which is designed to keep your vehicle centered in its lane. If this code is present, your car may not provide the necessary assistance, making it harder to maintain lane discipline. This can lead to unsafe driving conditions, especially on highways.

What are the most common causes of C0B21 and how much does it cost to fix?

Common causes include malfunctioning sensors, wiring issues, and improper calibration. Repair costs can range from $150 for a sensor replacement to $100 for wiring repairs and up to $150 for software updates.

Can I drive my car with C0B21 or should I stop immediately?

While you can technically drive with C0B21, it's not recommended. The lack of lane departure assistance increases the risk of drifting out of your lane, especially during long drives. It's best to address the issue as soon as possible for your safety.

How can I diagnose C0B21 myself using GeekOBD APP?

Using the GeekOBD APP, you can scan your vehicle for DTC codes, including C0B21. The app allows you to view real-time data from the lane departure system and check for any freeze frame data that can help identify the issue. Make sure to check for any visible sensor obstructions.

What vehicles are most commonly affected by C0B21?

C0B21 is frequently reported in vehicles such as the 2015-2018 Honda Accord, 2016-2019 Toyota Camry, and various Ford models with lane departure warning systems. Always check for any recalls or technical service bulletins related to your specific model.

How can I prevent C0B21 from happening again?

Regular maintenance is key to preventing C0B21. Keep the camera and sensors clean and free from obstructions. If you replace your windshield, ensure proper recalibration of the lane departure system. Additionally, staying updated with software updates can help prevent glitches.

What is C0B21?

DTC C0B21 is a diagnostic trouble code that indicates a problem related to the vehicle's advanced driver assistance systems (ADAS), particularly focusing on the lane departure warning system. This code often arises when the vehicle's sensors detect an anomaly in their operation or communication. For instance, it may signal that the vehicle's camera or radar system is not functioning correctly, which is crucial for features that help keep the car centered in its lane. When C0B21 is triggered, drivers can expect to see warning lights on their dashboard, specifically associated with lane departure or stability systems. Ignoring this code can lead to severe safety issues, as it compromises the vehicle's ability to assist in lane keeping. Additionally, vehicles equipped with this technology are becoming increasingly common, particularly in models like the 2015-2018 Honda Accord, Toyota Camry, and Ford Fusion. Therefore, understanding this code is essential for maintaining vehicle safety and functionality. Addressing C0B21 promptly not only ensures the reliability of advanced safety features but also enhances the overall driving experience by restoring confidence in the vehicle's systems.

System: C - Chassis (ABS, Steering, Suspension)

Symptoms

Common symptoms when C0B21 is present:

  • The check engine light or lane departure warning light remains illuminated on the dashboard, indicating a malfunction in the system.
  • The vehicle may exhibit erratic steering assistance, causing it to drift without driver input, which can be alarming during highway driving.
  • Drivers may notice that the lane departure warning system fails to activate or provide alerts when the vehicle approaches lane markings.
  • In some cases, the car's adaptive cruise control features may also become disabled, limiting the vehicle's functionality.
  • Increased driver fatigue may occur due to the lack of assistance in maintaining lane positioning, especially during long drives.

Possible Causes

Most common causes of C0B21 (ordered by frequency):

  1. The most common cause of DTC C0B21 is a malfunctioning lane departure warning system sensor, which has a likelihood of around 60%. This can be due to dirt or obstructions on the camera lens.
  2. Another potential cause is internal wiring faults or corrosion in the connections, which might disrupt the communication between components, accounting for about 25% of cases.
  3. Improper calibration after a windshield replacement can also lead to this code being triggered. If the camera is not aligned correctly, it won't function properly.
  4. Less commonly, a software glitch within the vehicle's computer systems could result in false readings, though this is rare.
  5. In exceptional cases, external factors like severe weather conditions or heavy fog can confuse the sensors, leading to erroneous readings.

C0B21 Repair Costs

Cost Breakdown by Repair Type

Sensor Replacement

Replacement of the malfunctioning lane departure warning sensor, including labor.

  • Total: $150 - $400
  • Success rate: 95%
Wiring Repair

Repairing or replacing damaged wiring and connectors related to the lane departure system.

  • Total: $100 - $250
  • Success rate: 90%
Software Update

Performing a software update or calibration on the system to resolve glitches.

  • Total: $75 - $150
  • Success rate: 85%
Money-Saving Tips for C0B21
  • 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 C0B21 Diagnosis Process

Follow these systematic steps to accurately diagnose C0B21. 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).

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: 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).

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: Component testing - Use a multimeter to check the voltage and continuity of the lane departure warning system sensors (20-30 minutes)

Step 3: Component testing - Use a multimeter to check the voltage and continuity of the lane departure warning system sensors (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: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes)

Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (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: Road test verification - Drive the vehicle under various conditions to confirm repair success, focusing on lane keeping features (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success, focusing on lane keeping features (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: 2016 Honda Accord Lane Departure System Repair

Vehicle: 2016 Honda Accord, 55,000 miles

Problem: Customer reported the lane departure warning light was constantly on.

Diagnosis: After running a diagnostic scan, DTC C0B21 was found. A visual inspection revealed the camera was obstructed by dirt.

Solution: The camera was cleaned, and the system was recalibrated using the GeekOBD APP.

Cost: $120 (cleaning and recalibration)

Result: The lane departure warning system functioned normally after the repair.

Case Study 2: 2017 Toyota Camry Sensor Replacement

Vehicle: 2017 Toyota Camry, 40,000 miles

Problem: Customer experienced intermittent lane departure warnings and system failures.

Diagnosis: Diagnostic testing revealed a malfunctioning lane departure sensor, triggering C0B21.

Solution: The faulty sensor was replaced, and the system was tested for proper function.

Cost: $300 (sensor replacement and labor)

Result: Post-repair, the lane departure system worked flawlessly.

Diagnose C0B21

Use GeekOBD APP for professional diagnosis!

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

Code: C0B21
System: Chassis (ABS, Steering, Suspension)
Severity: HIGH
Category: Chassis Codes