B0402 Code - Immobilizer Key Collation NG
Quick Answer
The B0402 diagnostic trouble code indicates that there is an issue with the immobilizer key collation in the vehicle. Common causes include Faulty immobilizer system, Damaged key transponder, Weak key battery. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B0402 indicates Immobilizer Key Collation NG.
- Common causes
- Common causes include Faulty immobilizer system, Damaged key transponder, Weak key battery.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code B0402 Description
The B0402 diagnostic trouble code indicates that there is an issue with the immobilizer key collation in the vehicle. The immobilizer system is designed to prevent the engine from starting unless the correct key is used. When the key collation is not successful, it means that the key is not being recognized by the immobilizer system, leading to starting issues or engine shutdown.
Common Causes of B0402
- Faulty immobilizer system
- Damaged key transponder
- Weak key battery
- Communication error between key and immobilizer system
Symptoms of B0402
- Engine cranks but does not start
- Intermittent stalling or engine shutdown
- Security light flashing on the dashboard
- Inability to start the vehicle with the key
How to Fix B0402
- Check the key battery: Ensure that the key battery is not weak or dead. Replace the key battery if necessary.
- Inspect the key transponder: Check the key transponder for any damage or malfunction. Replace the key if needed.
- Test the immobilizer system: Use a diagnostic tool to test the immobilizer system for any faults. Repair or replace components as required.
- Reprogram the key: If the key is not being recognized, reprogramming the key to the immobilizer system may resolve the issue.
- Clear the trouble code: After completing the repairs, clear the B0402 code from the vehicle's memory using a diagnostic tool.
Cost to Fix B0402
The typical repair costs for addressing the B0402 code can vary depending on the specific cause of the issue. Replacement key batteries or transponders may cost between $20 to $100, while diagnosing and repairing the immobilizer system can range from $100 to $500 or more. Labor costs can add an additional $80 to $150 per hour, depending on the repair shop's rates. It is advisable to consult with a professional mechanic to get an accurate estimate based on your vehicle's make and model.
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Code B0402 Information for Specific Makes
- B0402 Subaru — Immobilizer Key Collation NG
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