Ford Explorer: Passive Anti-Theft System (PATS) / Description and Operation - Passive Anti-Theft System (PATS) - System Operation and Component Description

System Operation

System Diagram

Network Message Chart

  Module Network Input Messages - BCM

  Module Network Input Messages - PCM

  Module Network Input Messages - ABS Module

PATS

The PATS function is controlled by the BCM, ABS module the PCM and the SOBDMC (if equipped). There are 2 main checks the PATS performs before allowing the vehicle to start.

If either of these checks fail, the PATS does not allow the vehicle to start.

• The BCM verifying a programmed key when it is inserted into the ignition lock cylinder.
• The PCM verifying the BCM identification to make sure it matches the identification stored in memory when the ignition state changes to RUN or START.

When the BCM determines a key is inserted into the ignition lock cylinder, it generates a challenge message. It sends the challenge message to the PATS transceiver over a LIN-based circuit. The transceiver reads the key and generates a response message to the BCM. If the message received from the PATS transceiver does not match a key stored in the BCM memory, the BCM does not respond to the PCM challenge request when the ignition transitions from OFF to ON.

The BCM activates the wake-up control circuit when a key is inserted into the ignition lock cylinder or a remote start request is received (if equipped with factory remote start).

The BCM wakes up the PCM by supplying voltage on the wake-up control circuit.

Once the PCM is awake the PCM sends the BCM a challenge message over the HS-CAN. When the BCM receives the challenge message, it generates a response and sends it back to the PCM. If the response from the BCM does not match the data in the PCM memory, this check fails and the vehicle does not start.

When the ignition transitions from OFF to ON and the modules initialize, the PCM sends a target 1 challenge request, the SOBDMC sends a target 2 challenge request (if equipped), and the ABS module replies to a target 1 challenge request to the PCM. The BCM replies and if the correct identification is received, the PATS disables and allows the vehicle to start. If the PATS prevents the vehicle from starting, a DTC sets in one of the modules.

If both the ABS and the PCM identification and key verification pass, the PATS allows the vehicle to start. The PATS cannot disable or stall a vehicle that is already running.

The BCM controls the ignition modes and, in conjunction with the PCM and ABS, controls the PATS.

PATS Parameter Identifications (PIDs)

In conjunction with Diagnostic Trouble Codes (DTCs), the PATS Parameter Identifications (PIDs) are a useful tool when diagnosing PATS concerns.

  BCM PID Chart

  PCM PID Chart

Component Description

BCM

When the BCM is replaced, program at least 2 keys and perform the parameter reset procedure.

The BCM requires PMI when replaced.

IKT

The IKT incorporates both the PATS functions and the RKE transmitter functions in a single device.

During key programming procedures, the PATS and the RKE transmitter of an IKT are programmed into the BCM. Conventional PATS keys can also be programmed to the vehicle if requested by the customer.

A minimum of 2 and a maximum of 6 keys can be programmed (unless in unlimited key mode).

PATS Transceiver

The PATS transceiver reads any key placed in the ignition lock cylinder. When the ignition changes to RUN or START, the BCM activates the PATS transceiver. Once the PATS transceiver activates, it activates the key in the ignition lock cylinder and receives the key data. Once the PATS transceiver receives the key data, it sends the data to the BCM.

PCM

When the PCM is replaced, perform the parameter reset procedure. There is no need to program keys if the PCM is replaced.

The PCM requires PMI when replaced.

SOBDMC

When the SOBDMC is replaced, perform the parameter reset procedure. There is no need to program keys if the SOBDMC is replaced.

The SOBDMC requires PMI when replaced.

ABS Module

When the ABS module is replaced, carry out the PMI and parameter reset procedures. There is no need to program keys if the ABS module is replaced.