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P codepowertrainMedium severity

P0513Incorrect Immobilizer Key

The immobilizer system has detected a key whose transponder code does not match what the vehicle expects.

Definition

The immobilizer antenna around the ignition lock reads the transponder chip in the key and passes its code to the immobilizer/PCM for validation before enabling fuel and spark (or starter release). P0513 sets when a key is read but its code is not recognized as one programmed to the vehicle. The typical symptom is an engine that cranks but will not start, or starts and immediately stalls, usually with the security lamp flashing; the vehicle is disabled until a valid key is used or programmed.

Common causes

  • Unprogrammed spare or newly cut transponder key
  • Damaged or dead transponder chip in the key head
  • Interference from a second transponder key or metal fobs on the same key ring
  • Faulty immobilizer antenna ring at the ignition cylinder
  • Wiring or communication fault between the immobilizer module and PCM
  • Immobilizer module or PCM data mismatch after module replacement

Common misdiagnoses

  • Starter motor
  • Fuel pump
  • Ignition switch
  • PCM replaced without addressing key programming

Troubleshooting steps

  1. 1.Try a known-programmed key

    Attempt a start with the vehicle's other original key, held alone with no other keys or fobs on the ring; success confirms a bad or unprogrammed key.

  2. 2.Check the security indicator

    Note the security/immobilizer lamp behavior during cranking; a flashing lamp confirms the no-start is immobilizer-related rather than fuel or ignition.

  3. 3.Read immobilizer module codes

    Scan the immobilizer/body module for supporting codes that distinguish an unreadable key (antenna fault) from a read-but-invalid key.

  4. 4.Program the key

    If the key is unrecognized, program it to the vehicle with a capable scan tool following the security access procedure.

  5. 5.Test the antenna ring and wiring

    If all keys fail, check power, ground, and data lines at the antenna ring around the lock cylinder and replace the ring if it fails the read test.

  6. 6.Verify module pairing

    If a PCM or immobilizer module was recently replaced, perform the manufacturer's module-to-vehicle security relearn so stored key codes match.

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