P1260critical severityPowertrain
Anti-Theft System Signal Engine Disabled
on 2019 Mazda Mazda3 2.5L I4 · FWD
What this code means
The anti-theft immobilizer system has detected an unauthorized start attempt and has disabled the engine. The PCM will not allow fuel injection or ignition until proper key authentication is received.
Symptoms
- Engine cranks but will not start
- Security light flashing on dashboard
- No fuel delivery or spark
- Engine starts then immediately dies
Common causes
- Key transponder not recognized
- Faulty immobilizer antenna around ignition
- Incorrect or damaged key
- Immobilizer module failure
- Low key battery (push-button start systems)
Diagnostic steps
- Try a second programmed key
- Check security indicator light behavior
- Inspect immobilizer ring antenna around ignition cylinder
- Verify key programming status with scan tool
- Check key battery if applicable
Repair notes
Try a different programmed key first; reprogram keys or replace the immobilizer antenna if faulty.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1