P0513 means the ECU has detected an incorrect or invalid immobilizer key signal — in simple terms, the vehicle’s anti-theft system does not recognize the key you’re trying to start the engine with. When this happens, the ECU disables fuel injection or starter operation, preventing the engine from running. You may experience no-start conditions, intermittent starting, or a flashing immobilizer light. In this guide, you’ll learn exactly what P0513 means, the symptoms, the most common causes, step-by-step diagnostics, and the fixes that typically resolve this immobilizer fault.
What Does P0513 Mean?
P0513 sets when the ECU receives an incorrect, missing, or corrupted transponder key signal from the vehicle’s immobilizer system. Modern vehicles use a transponder chip inside the key or key fob, which communicates with the immobilizer antenna and body control module (BCM). If the transmitted code doesn’t match what’s stored in memory — or if the signal is weak or unreadable — the ECU blocks the start sequence and logs P0513.
This can occur from a damaged key chip, interference, a failing antenna ring, BCM communication issues, or incorrect key programming. In some cases, battery failure inside a smart key fob prevents proper authentication.
Quick Reference
- OBD-II Family: P-Code (Powertrain)
- Scope: Generic
- System: Immobilizer / Key Authentication
- Difficulty Level: Moderate
- Estimated Repair Cost: €20–€250
- Last Updated: 2025-11-24
Real-World Example / Field Notes
P0513 is extremely common on Chrysler, Dodge, Jeep, Hyundai, Kia, and GM vehicles. One Dodge Journey case involved a no-start condition with a flashing red immobilizer light. The key looked fine, but the transponder chip inside had partially detached from years of dropping the fob. A new key programmed with a diagnostic tool immediately restored normal operation. On Hyundai models, a weak fob battery often prevents proper signal transmission during push-button start, resulting in a P0513 even though the fob still locks/unlocks the car.
Symptoms of P0513
- No-start condition: Engine cranks or doesn’t crank but will not run.
- Immobilizer light flashing: Indicates failed key authentication.
- Intermittent starting: Key sometimes works, sometimes doesn’t.
- Key not recognized message: Common on push-button or smart key systems.
- Security mode activation: Vehicle may disable starter after repeated failed attempts.
- Remote functions working but no start: Fob battery too weak for immobilizer signal.
Common Causes of P0513
Most Common Causes
- Damaged or unprogrammed transponder key.
- Weak or dead key fob battery (smart key systems).
- Faulty immobilizer antenna ring around the ignition.
- Incorrect or corrupted key programming.
- Poor connection at BCM or immobilizer module.
Less Common Causes
- Aftermarket keys with incompatible transponders.
- Electrical interference from nearby devices or metal objects.
- Water-damaged key fob electronics.
- Faulty BCM or immobilizer control module.
- Wiring faults between the immobilizer and ECU.
Diagnosis: Step-by-Step Guide
Your goal is to determine whether the key, the immobilizer antenna, or the modules are failing to communicate properly.
Tools You’ll Need: OBD-II scanner, multimeter, working spare key (if available), key programmer (optional), and basic hand tools.
- Try a spare key first. If the spare starts the engine normally, the original key’s transponder chip is defective.
- Check the immobilizer light. A rapid flashing pattern typically means the key is not recognized.
- Replace the key fob battery. Weak fob batteries often cause push-button vehicles to fail authentication while still unlocking doors.
- Inspect the immobilizer antenna ring. Look for cracks, loose connectors, or corrosion around the ignition cylinder.
- Check for wiring damage. Inspect harnesses between the antenna, BCM, and ECU.
- Scan live data. Many systems display “Key Authenticated: Yes/No.” This instantly confirms where the failure occurs.
- Reprogram the key. If the immobilizer memory was wiped or corrupted, reprogramming the key(s) restores function.
- Check the BCM. Look for communication faults or module DTCs that accompany P0513.
- Test for interference. Remove metal objects, other keys, or RFID tags from your keychain and retry.
- Evaluate the ECU. Rare, but ECU integration faults can block key authentication.
Pro Tip: On many vehicles, placing the key fob directly against the start button or near the steering column bypasses weak fob battery issues — if the engine starts, replace the battery immediately.
Possible Fixes & Repair Costs
- Replace key fob battery: €2–€10 (smart keys).
- Program a new key: €60–€150 depending on model.
- Replace immobilizer antenna ring: €30–€80.
- Repair wiring or connectors: €10–€60.
- Replace BCM or immobilizer module: €120–€250.
- Replace damaged key fob or chip: €40–€120.
Always verify whether the fault lies in the key itself before replacing immobilizer components — most P0513 issues are key-related, not module-related.
Can I Still Drive With P0513?
Usually, no. P0513 almost always results in a no-start condition, meaning the vehicle cannot be driven until the immobilizer recognizes a valid key. If the issue is intermittent, you may be able to start the engine occasionally, but it’s unreliable and can leave you stranded. Address the problem promptly.
Related Codes
- P0574 – Cruise Control System Vehicle Speed Too High
- P0573 – Brake Switch “A” Circuit High
- P0572 – Brake Switch “A” Circuit Low
- P0571 – Brake Switch “A” Circuit
- P0570 – Cruise Control Accelerate Signal
- P0569 – Cruise Control Coast Signal
- P0568 – Cruise Control Set Signal
- P0567 – Cruise Control Resume Signal
- P0566 – Cruise Control Off Signal
- P0565 – Cruise Control On Signal
Key Takeaways
- P0513 indicates the immobilizer does not recognize the key or fob.
- Most issues are caused by a bad key, weak fob battery, or antenna ring failure.
- The vehicle may not start at all until the issue is corrected.
- A spare key and live data checks quickly confirm the root cause.
FAQ
What causes P0513 most often?
Usually a damaged transponder chip, weak key fob battery, or faulty immobilizer antenna. These prevent the ECU from verifying the key.
Can a dead fob battery trigger P0513?
Yes. Smart-key systems rely on internal fob power for communication. A dead battery can unlock the car but still fail immobilizer authentication.
Is P0513 the same as a bad key?
Often yes, but not always. Wiring issues, BCM faults, or interference can also cause this code even with a healthy key.
Can I drive with P0513?
Not if the engine will not start. If the issue is intermittent, driving is possible but risky as the car may fail to restart later.
How do I fix P0513?
Try a spare key, replace the fob battery, inspect the antenna ring, scan for immobilizer faults, and reprogram the key if needed. Most cases are resolved with key repair or replacement.