Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Passive Anti-Theft System (PATS) Operation
The PATS function is controlled by the IPC . With this type of PATS , there are parameters that need to be reset if either the IPC or the PCM (or both) are replaced. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) PARAMETER RESET - INTEGRATED KEYHEAD TRANSMITTER (IKT) .
When the PATS key is turned to the ON or START position, the IPC initiates the key interrogation sequence by sending a voltage signal to the PATS transceiver. The transceiver then uses its antenna to bounce a signal off the transponder in the PATS key. This process "reads" the PATS key identification code and sends the key identification code back to the IPC , which interprets it and determines if it matches one of the stored keycodes. If it does match one of the stored keycodes, the IPC sends a message to the PCM to ground the starter relay solenoid coil and to also allow the fuel injectors to operate. If it does not match one of the stored keycodes, or it is only a partial key read or no key read, the IPC sends a message to the PCM to not ground the starter relay solenoid coil and not allow fuel injector operation. The anti-theft indicator in the IPC flashes (or may glow steadily) and the IPC stores one or more DTCs.
All elements of PATS must be functional before the vehicle starts. If any of the components are not working correctly, the vehicle cannot start.
If the IPC must be replaced for any reason (PATS issues or IPC issues), the PATS keys must also be programmed into the new IPC . Refer to KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT - INTEGRATED KEYHEAD TRANSMITTER (IKT) .
PATS disables the vehicle from starting if there is:
- a damaged PATS key.
- a non-programmed PATS key.
- a non- PATS key (key has no electronics).
- damaged wiring.
- a damaged transceiver.
- a damaged IPC .
- a damaged PCM.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.