Passive Anti-Theft System (PATS) - System Operation and Component Description

No Key Detected Message

There are 2 scenarios in which the No Key Detected message displays in the message center.

The first is when the ignition is off, the START/STOP button is pressed and a programmed passive key is not detected inside the vehicle. If a component failure (such as a dead passive key battery) is causing the No Key Detected message to display, the backup starting method can be used.

The second scenario is when the vehicle ignition is on, the driver exits the vehicle with the programmed passive key and closes the door.

The BCM activates the PATS front antenna, the keyless entry rear antenna and both exterior door handle keyless entry antennas to search the inside of the vehicle for a passive key any time a door is opened and then closed with the ignition on and the first time each drive cycle the vehicle speed exceeds 15 km/h (9 mph). The No Key Detected message displays in the message center and the horn chirps twice when the ignition is on and a passive key is no longer detected inside the vehicle.

This strategy deters the passive key from being separated from an already running vehicle. If a passive key is no longer in the vehicle, the ignition remains on and the vehicle continues to operate. When the START/STOP button is pressed to turn the ignition off, the ignition can be restarted without a passive key present inside the vehicle for approximately 20 seconds. After 20 seconds have elapsed, a passive key must be present to transition the ignition out of off.

Component Description

Passive Key

The passive key incorporates both the PATS and the RKE transmitter functions in a single device. The passive key must be located inside the vehicle for the ignition to transition out of off and on the outside for keyless entry features. During key programming procedures, the PATS and the RKE transmitter of the passive key are both programmed into the BCM. Passive keys are programmed into the BCM using the passive key backup starting location. The vehicle accepts programming of up to 4 passive keys.

The passive key receives the low frequency signals from the PATS front antenna and the keyless entry rear antenna. When the passive key is activated by one of the low frequency signals, it sends out a high frequency signal that is received by the RTM. The passive key also contains a removable key blade that unlocks the driver door in the event of an electrical failure (such as a drained battery).

PATS Front Antenna

The PATS front antenna is wired to the BCM. When activated by the BCM, it transmits a low frequency signal that activates a passive key. This antenna serves a dual purpose in that it can detect a passive key in the backup starting location. The backup starting location is used to program passive keys and to detect a programmed passive key in the event the battery in the programmed passive key has failed.

When activated, the PATS front antenna sends out a low frequency signal with an approximate range of 1 m (3 ft). A valid programmed passive key must be within range for the PATS to recognize the key and allow the ignition to transition out of off.

If a passive key is placed in the far outside edges of the interior, such as above a sun visor or in a door map pocket, the vehicle can experience a PATS concern. If the passive key is located in one of these areas and there is a PATS concern, move the passive key out of the area and attempt to transition the ignition on. If the key is outside the range of the PATS front antenna and the keyless entry rear antenna when the START/STOP button is pressed, the No Key Detected message displays in the message center.

Keyless Entry Rear Antenna