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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1505 (Anti-Theft System - Passive Anti-Theft System (Pats) - (Except Hybrid)) >> Diagnosis And Testing >> Anti-Theft >> Principles of Operation >> Passive Anti-Theft System (PATS) Operation

Passive Anti-Theft System (PATS) Operation

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The PATS  function is controlled by the IC  . With this type of PATS  , there are parameters that need to be reset if either the IC  or the PCM (or both) are replaced. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) PARAMETER RESET .

When the PATS  key is turned to the ON or START position, the IC  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 IC  , which interprets it and determines if it matches one of the stored key codes. If it does match one of the stored key codes, the IC  sends a message to the PCM to ground the starter relay solenoid coil and allow the fuel injectors to operate. If it does not match one of the stored key codes, or it is only a partial key read or no key read, the IC  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 IC  flashes (or may glow steadily) and the IC  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 IC  must be replaced for any reason (PATS  concerns or IC  concerns), the PATS  keys must also be programmed into the new IC  . Refer to INTEGRATED KEYHEAD TRANSMITTER (IKT) KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT .

PATS  is active only for a few seconds when the vehicle is starting. It is not a PATS  concern if the vehicle stalls after it has been running for a minimum of 3 seconds. PATS  does not disable a running vehicle.

A PATS  no-start may involve a vehicle no-start due to either the fuel injectors not operating or the starter not operating (or both). If the PATS  anti-theft indicator does not prove out and one (or both) of the previous conditions are present, it may be due to a PATS  issue. If the anti-theft indicator proves out, and the vehicle does not start, it is probably not a PATS  issue. Refer to the INTRODUCTION - GASOLINE MODELS . If the anti-theft indicator does not illuminate at all, it may be an IC  issue. Refer to the SYMPTOM CHART  in this article for information. A low battery voltage condition may cause the PATS  to allow starter operation, but may keep the fuel injectors from operating.

PATS  disables the vehicle from starting if there is: