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Home/DTC Codes/Ford/Explorer/2002-2005 4.6L V8/P1259
P1259

Immobilizer to PCM Signal Error

2002-2005 Ford Explorer 4.6L V8

High SeverityPowertrain

Description

The PATS (Passive Anti-Theft System) immobilizer is not communicating properly with the PCM. The security signal between the instrument cluster and PCM does not match, preventing proper engine operation.

Symptoms

  • Check Engine Light
  • Engine may not start
  • Security light flashing
  • Engine starts then dies

Common Causes

  • Faulty transponder key
  • PATS transceiver malfunction
  • Instrument cluster communication error
  • PCM not properly programmed
  • Low battery voltage during key programming

Diagnostic Steps

  1. Try a different programmed key
  2. Check PATS indicator light behavior
  3. Verify key is programmed (check NUMKEYS PID)
  4. Inspect PATS transceiver around ignition cylinder
  5. Check battery voltage

Repair Notes

Try second key. Reprogram keys if needed. Replace PATS transceiver if faulty. May require dealer-level scan tool.

Related Codes

P1260Theft Detected — Vehicle ImmobilizedP1260Theft Detected — Vehicle ImmobilizedP1260Anti-Theft System Signal Engine DisabledP1260Theft Detected — Vehicle ImmobilizedP1269Immobilizer Code Not ProgrammedP1269Immobilizer Code Not ProgrammedP1269Immobilizer Code Not Programmed

Other Powertrain Codes

P1259 on Other Vehicles

Ford Aerostar

1990-1997 3.0L V6

Ford Aerostar

1990-1997 4.0L V6

Ford Bronco

1990-1996 4.9L I6 300

Ford Bronco

1990-1996 5.0L V8 302 Windsor

Ford Bronco

1990-1996 5.8L V8 351 Windsor

Ford Bronco

2021-2024 2.3L I4 EcoBoost

Ford Bronco

2021-2024 2.7L V6 EcoBoost

Ford Bronco Raptor

2022-2024 3.0L V6 EcoBoost

Common Questions

What does code P1259 mean on a 2002-2005 Ford Explorer?

P1259 stands for "Immobilizer to PCM Signal Error". The PATS (Passive Anti-Theft System) immobilizer is not communicating properly with the PCM. The security signal between the instrument cluster and PCM does not match, preventing proper engine operation.

What are the symptoms of P1259 on a Ford Explorer?

Common symptoms of P1259 include: Check Engine Light, Engine may not start, Security light flashing, Engine starts then dies.

What causes P1259 on a 2002-2005 Ford Explorer?

Common causes of P1259 include: Faulty transponder key, PATS transceiver malfunction, Instrument cluster communication error, PCM not properly programmed, Low battery voltage during key programming.

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