Immobilizer to PCM Signal Error
2000-2003 Ford Excursion 7.3L V8 Power Stroke Diesel
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
- Try a different programmed key
- Check PATS indicator light behavior
- Verify key is programmed (check NUMKEYS PID)
- Inspect PATS transceiver around ignition cylinder
- 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
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1259 on Other Vehicles
Common Questions
What does code P1259 mean on a 2000-2003 Ford Excursion?
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 Excursion?
Common symptoms of P1259 include: Check Engine Light, Engine may not start, Security light flashing, Engine starts then dies.
What causes P1259 on a 2000-2003 Ford Excursion?
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.