System Operation

Passive Anti-Theft System (PATS) - without Intelligent Access (IA)

System Operation

System Diagram





Network Message Chart

Module Network Input Messages - BCM (Body Control Module)





Module Network Input Messages - PCM (Powertrain Control Module)






Passive Anti-Theft System

The PATS (Passive Anti-Theft System) is controlled by the BCM (Body Control Module). There are 2 main checks that PATS (Passive Anti-Theft System) performs before allowing the engine to start. If either of these checks fail, PATS (Passive Anti-Theft System) does not allow the engine to start. The first of the 2 checks is to verify that a programmed key was used to turn the ignition to the ON or START position. The second check is the BCM (Body Control Module) and PCM (Powertrain Control Module) verifying their identification to make sure they match the identification stored in memory.

When the BCM (Body Control Module) determines the ignition has been turned to the ON or START position, it generates a challenge message. It sends the challenge message to the PATS (Passive Anti-Theft System) transceiver on the transmit (TX) circuit. The transceiver in turn reads the key and generates a response message that is sent back to the BCM (Body Control Module) on the receive (RX) circuit. If the message received from the transceiver does not match a key stored in the BCM (Body Control Module) memory, the engine will not start.

Once the BCM (Body Control Module) verifies a programmed key is in the ignition, PATS (Passive Anti-Theft System) performs the second check. The second check is initiated by the BCM (Body Control Module) waking up the PCM (Powertrain Control Module) by supplying voltage on the wakeup control circuit. The BCM (Body Control Module) activates the wakeup control circuit when:

- the driver door is opened.

- a key is inserted into the ignition.

- or when the ignition is in the ON or START position.

Once the PCM (Powertrain Control Module) is awake, the PCM (Powertrain Control Module) sends the BCM (Body Control Module) a challenge message over the HS-CAN (High Speed Controller Area Network). When the BCM (Body Control Module) receives the challenge message, it generates a response and sends it back to the PCM (Powertrain Control Module). If the response from the BCM (Body Control Module) does not match the response in the PCM (Powertrain Control Module) memory, this check fails and the engine will not start.

If both the PCM (Powertrain Control Module) identification and key verification pass, PATS (Passive Anti-Theft System) allows the engine to start. PATS (Passive Anti-Theft System) cannot disable or stall an engine that has already been started.

PATS (Passive Anti-Theft System) PIDs (Parameter Identifications)

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

BCM (Body Control Module) - Module PID Chart





PCM (Powertrain Control Module) - Module PID Chart