P0513
PowertrainIncorrect Immobilizer Key
When you turn the key or hit start, the immobiliser sends a coded challenge to the transponder chip in your key and waits for the right answer back. If that handshake fails or never happens, the ECU refuses to let the engine run and logs P0513. For you, that means the engine cranks over but won't fire, because the car has decided the key it's seeing isn't one it trusts.
ⓘ Information only. This page provides general educational information about fault code P0513. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0513 mean?
P0513 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Incorrect Immobilizer Key.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine turns over normally on the starter but won't catch and run
- • A key or padlock symbol on the dash, usually flashing rather than steady
- • Security or anti-theft warning light staying lit
- • Check engine light alongside the immobiliser warning
- • Car sometimes starts on a spare key but not the main one
- • Occasionally fires up after sitting for a few minutes, then refuses again
Possible causes
Causes commonly associated with P0513, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Replacement or cut key that's never been properly coded to the car, very common after buying a cheap eBay key or a spare from a locksmith who didn't finish the job
- 2. Transponder chip in the key damaged by water, a dropped fob, or a leaking fob battery corroding the board
- 3. Weak or dead fob battery on push-button start cars, so the chip can't respond strongly enough to the antenna
- 4. Immobiliser antenna ring around the ignition barrel gone faulty or corroded, so it can't read the chip even though the key is fine
- 5. Broken or corroded wiring between the antenna ring and the immobiliser module, often where the loom flexes near the column
- 6. Loss of sync between the immobiliser module and the ECU, which can follow an ECU reflash, a flat main battery, or module replacement
- 7. Someone has tried to nick the car or jam the system, which trips the immobiliser as designed
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Try a known-good second key first. If the car starts on the spare and not the main key, you've found your fault and saved yourself a load of diagnosis
- 2. Scan for codes and read the immobiliser live data. A decent tool will show whether the module is even seeing the transponder when you crank, which tells you antenna versus key
- 3. Check the obvious on push-start cars and swap the fob battery before anything else, it's a couple of quid and rules out a lazy chip
- 4. Inspect the key itself for cracks, water marks, or green battery corrosion inside the fob housing
- 5. Check for column wiring and antenna ring faults, looking for breaks or corrosion where the loom moves with the steering
- 6. If the hardware checks out, it's down to recoding the key or re-syncing the immobiliser to the ECU with a tool that has security access for your make
Common questions about P0513
Can I sort this out myself or do I need a specialist? +
You can do the cheap bits at home. Fit a fresh fob battery, clean any corrosion off the chip, and try your spare key, that covers a fair few of these. What you can't do on most cars from the last fifteen years or so is code a new key or re-sync the immobiliser, because that needs a scan tool with manufacturer security access. A mobile auto locksmith is usually cheaper than the main dealer for that and will come to your driveway. Reckon on roughly £80 to £150 for a coded key and programming at an independent, more at a franchised dealer.
If I clear the code, will it stay gone? +
Only if the key actually got recognised in the meantime. P0513 is a record of a failed handshake, so wiping it does nothing about the cause. If you've coded a working key or fixed the antenna, the code clears and stays clear once the car starts properly. If you just delete it and try the same dodgy key, it logs straight back as soon as you crank. Clearing codes is not a fix here, it's just housekeeping after the real repair.
What's the risk if I just leave it and keep trying? +
The main risk is being stranded, because the car won't start at all once this is set. There's no danger of driving on it like a misfire, the immobiliser simply locks you out. The thing to watch is repeated failed attempts on some systems triggering a longer lockout timer, so hammering the start button over and over can leave you waiting ten or fifteen minutes before it'll even let you try again. Sort the key or antenna properly rather than relying on it eventually catching.
How quickly do I need to deal with this? +
As soon as you can, since a car that won't start isn't much use sat on the drive. It's not an emergency in the sense of anything getting damaged by waiting, the engine just won't run. If it's intermittent and still starting on the spare, get it looked at before the good key gives up too and you're properly stuck. If you've only got one key and it's failing, book an auto locksmith sooner rather than later, because being down to a dead transponder with no backup is the worst spot to be in.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →