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P0513 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0513 is an OBD-II Code that refers to Incorrect Immobilizer Key


A P0513 code is caused by an ECM (Engine Control Module) receiving a signal from the PCM that the Immobilizer Key is not present or is invalid. The immobilizer system prevents your car from being stolen by requiring an electronic key (fob) to be present when starting the car. Without the key, the engine will refuse to start (or run). When this occurs, the PCM (powertrain control module) signals the ECM and a code is set and stored in memory.


Common causes for this code include:

  • A faulty immobilizer system
  • A faulty starter or starter relay
  • An open in the key fob’s circuit
  • A problem with the PCM (powertrain control module)
  • Faulty immobilizer key or antenna


The symptoms of a P0513 code are:

  • MIL (Malfunction Indicator Lamp) illuminated
  • Engine will not start


To diagnose a P0513 DTC code, a technician would:

  1. Scan for codes in the ECM and immobilizer system
  2. Inspect the fob’s circuit for shorts, opens or a poor connection
  3. Inspect the starter and starter relay 
  4. Perform a PCM input/output test on all circuits to ensure they are functioning properly 
  5. Replace any faulty components found during diagnosis
  6. Clear the codes from ECM memory and retest vehicle for proper operation.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0513 code:

  • Inspecting only one part of the circuit, i.e. starter or fob 
  • Replacing an ECM without first testing it to ensure that code was not present prior to replacement 
  • Relying on a single test to determine whether or not a faulty component is present
  • Not checking the freeze frame data

How serious is this?

The P0513 code can actually be very serious. This code is telling the vehicle’s computer that there is a problem with the immobilizer system and it may not be letting you start your car for a reason. For example, if someone managed to break into your car, they could hot-wire the starter, bypassing the immobilizer system and allowing them to steal your car without requiring a key.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Replacing the starter relay 
  • Replacing the faulty starter
  • Replacing the ECM (powertrain control module) if it has trouble passing I/O tests or codes are present prior to replacement, or after replacing a component in the immobilizer system
  • Replacing the immobilizer key fob battery
  • Replacing any corroded connectors found during diagnosis, or any connector that fails the continuity test
  • Replacing a faulty immobilizer antenna or ECM 
  • Clearing the DTC from ECM memory and retesting vehicle for proper operation

Related codes

A P0513 is related to and may be accompanied by the following codes: 

P0758 – Key Fob Battery Voltage is Low

P0759 – Key Fob Battery Voltage is Very Low

P0760 – Key Fob Mechanical Problem

P0790 – Theft Deterrent System Voltage too Low During Vehicle Start

U0100 – Lost Communication With ECM/PCM


In conclusion, the P0513 code is a generic trouble code that means the computer has detected an issue with the Immobilizer Key and is experiencing an incorrect signal from the PCM. Troubleshooting this code is relatively simple and can be done in a few steps using logical diagnosis such as checking for a bad starter or starter relay, faulty fob battery or corrosion of the ECM’s connections. If repairs are performed, remember to clear the codes from the ECM and retest vehicle for proper operation after replacing any components found during diagnosis.