System Operation
System Diagram
Item | Description |
---|---|
1 | BCM |
2 | IPC |
3 | Passive Key |
4 | RTM |
5 | GWM |
6 | GWM |
7 | PATS Center Antenna |
8 | Keyless Entry Rear Antenna |
9 | Ignition Switch |
10 | Front Door Keyless Entry Antenna(s) |
11 | PATS Enable |
12 | PCM |
13 | ABS |
14 | SOBDMC |
15 | Hybrid Vehicles |
Network Message Chart
BCM Network Input Messages
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
PATS start request target data | PCM | The PCM sends the BCM and the ABS module a challenge request for a valid ID. |
PATS start request target data | SOBDMC | The SOBDMC (if equipped) sends the BCM a challenge request for a valid ID. |
RKE data | RTM | The RTM sends the BCM programmed passive key information. |
IPC Network Input Messages
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
Vehicle mode | BCM | Used by the IPC to display No Key Detected when the START/STOP button is pressed and no programmed key is detected within the vehicle. |
PCM Network Input Messages
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
PATS control command | BCM | The response from the BCM supplying the PCM challenge ID. If the BCM ID response is incorrect, then the PATS prevents the vehicle from starting. |
Module Network Input Messages - SOBDMC (if equipped)
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
PATS control command | BCM | The response from the BCM supplying the SOBDMC target 2 challenge ID. If the BCM ID response is incorrect, then PATS prevents the vehicle from starting. |
ABS Module Network Input Messages
Broadcast Message | Originating Module | Message Purpose |
---|---|---|
Immobilizer target 1 function | PCM | The immobilizer subtarget function sends a response message to the target 1 challenge message from the PCM. |
PATS
The PATS function is controlled by the BCM, the PCM, ABS, and SOBDMC (if equipped).
When the START/STOP button is pressed, a voltage signal is sent to the BCM. When the BCM detects the START/STOP button is pressed, it begins the key initialization sequence by activating the PATS center antenna and keyless entry rear antenna. Each antenna transmits a low frequency signal with an approximate range of 1m (3ft). The passive key activates if it is within range of the antennas. The BCM is able to determine the passive key location (inside or outside the vehicle) based on the input from the antennas.
When the passive key activates, it sends the PATS identification code to the RTM via a high frequency signal. The RTM interprets the high frequency signal from the passive key and sends the information to the BCM over the LIN based circuit.
If a programmed passive key is detected inside the vehicle, the BCM transitions the ignition from OFF to ON.
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.
The PATS and the RKE system share operation of several components including the passive keys, the BCM, and the RTM.
If there is a concern with either of these components, the PATS and the RKE system are both affected.
In the event of a no start, place a programmed passive key in the backup location to allow the vehicle to start. The PATS center antenna activates the passive key when the START/STOP button is pressed in the event the batteries are depleted within the passive key.
NOTE: If available as a selection on the diagnostic scan tool, the passive start feature is a programmable parameter and can be enabled/disabled. If the feature is disabled, the features to passively enter and start the vehicle are inoperative. To start the vehicle, the passive key must be placed in the backup starting location.
The BCM controls the ignition modes and in conjunction with the PCM, ABS, and the SOBDMC (if equipped), 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
Acronym | Name | Description |
---|---|---|
KEYS_PROGMD | Number of ignition key codes supported | Displays the number of keys currently programmed into the BCM. |
MIN_KEYS_RQD | Minimum number of keys required | Minimum number of programmed keys required. This PID always reads 2. |
PCM PID Chart
Acronym | Name | Description |
---|---|---|
PATSENABL | Vehicle enable status | Indicates if the PATS allows the vehicle to be driven. Must read enabled for the vehicle to be driven. |
No Key Detected Message
NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS no-start if the passive key is within close proximity of the charger. If a concern is observed, move the passive key away from the charger and attempt to start the vehicle.
The No Key Detected message displays in the message center when:
The BCM activates all the PATS antennas to search the inside of the vehicle for a passive key every time a door or liftgate is opened and then closed. This strategy aids to prevent the passive key from being separated from an already running vehicle. If a passive key is no longer detected in the vehicle, the vehicle continues to run. If the START/STOP button is pressed to turn the vehicle OFF, the engine can be restarted without a passive key present inside the vehicle for approximately 20 seconds. During that time, Restart now or key is needed displays in the message center. After 20 seconds have elapsed, a passive key must be present to start the vehicle or transition the ignition out of ON.
Component Description
Passive Key
NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS concern if the passive key is within close proximity of the charger. If a concern is observed, move the passive key away from the charger and attempt to turn the ignition on.
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. See the Owner's Literature for maximum number of keys that can be programmed to the vehicle.
The passive key receives the low frequency signals from the PATS center antenna, the keyless entry door antennas 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 must be located inside the vehicle for the ignition to transition out of OFF and outside the vehicle for passive entry features.
The passive key also contains a removable key blade that unlatches the driver door in the event of an electrical failure (such as a drained battery). The passive key requires 1 battery. For battery replacement instructions, refer to the Owner's Literature.
PATS Center Antenna
NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS concern if the passive key is within a few inches of the charger and the No Key Detected message displays in the message center. If a concern is observed, move the passive key away from the charger and attempt to transition the ignition on.
The PATS center antenna is monitored and activated from 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 valid programmed passive key in the event the battery in the programmed passive key has failed.
A programmed passive key must be within the passenger compartment or the cargo area for the PATS to detect the passive key and allow the ignition to transition fron OFF to ON.
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 center 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
NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS concern if the passive key is within a few inches of the charger and the No Key Detected message displays in the message center. If a concern is observed, move the passive key away from the charger and attempt to transition the ignition on.
The keyless entry rear antenna is wired to the BCM. When activated by the BCM, it transmits a low frequency signal that activates a passive key.
A programmed passive key must be within the passenger compartment or the cargo area for the PATS to detect 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 the far corners of the luggage compartment, 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 keyless entry rear antenna and the PATS center antenna when the START/STOP button is pressed, the No Key Detected message displays in the message center.
Front Door Keyless Entry Antenna(s)
The keyless entry door antennas are wired to the BCM. When activated by the BCM, the antennas transmit a low frequency signal with an approximate range of 1 m (3 ft) to activate a passive key.
A valid programmed passive key must be within range for the PATS to operate.
If a passive key is placed in the far outside edges of the interior, such as the far corners of the luggage compartment, 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 determined by the BCM to be outside the vehicle or is outside the range of the keyless entry door antennas, the keyless entry rear antenna and the PATS center antenna when the START/STOP button is pressed, the No Key Detected message displays in the message center.
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 it is replaced.
SOBDMC (if equipped)
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 it is replaced.
BCM
If the BCM is replaced, carry out the PMI, program at least 2 keys and carry out the parameter reset procedure.
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.
Each door has a backup power system which allows the door to function if your vehicle has no power. The system has a limited number of operations before the power is depleted and turns off. When the system turns off, the door remains open and unlatched and does not close.
If your vehicle has no power and the backup power system is turned off, you can close and secure your vehicle by manually resetting each door latch using a key in the position shown.