Start/Stop Ignition Switch System (With Intelligent Access): Overview

The push-button ignition system uses the following components to achieve the 4 ignition modes (OFF, ACC, RUN and START):

• BCM
• BPP
• IA key
• RFA module
• Start/stop switch
• TPM module

To achieve any ignition mode other than OFF, the IA key must be present inside the vehicle. The driver does not need to perform any actions on or with the IA key to operate the push-button ignition system. It is sufficient that the IA key is located inside the vehicle when the start/stop switch is pressed. Pressing the start/stop switch causes the RFA module to send out a RF signal to the IA key. The IA key responds by transmitting a RF signal to the TPM module. The TPM module then sends a MS-CAN message to the RFA module that the IA key has responded. Next the RFA module sends a message over the MS-CAN to the BCM indicating that the correct IA key is present. Based on the start/stop switch and BPP switch inputs, theBCM activates the appropriate ignition mode.

Backup Transceiver 

If the battery inside the IA key is weak, damaged or if excessive ambient RFI prevents communication between the RFA module and the IA key, the backup transceiver located in the center console storage compartment provides a secondary means for the RFA module to validate the IA key and authorize use of the vehicle. The backup transceiver uses close range RF identification to exchange signals with the IA key, similar to the way an encoded PATS key and transceiver operate. For information on the IA key and backup transceiver, refer to Anti-Theft Passive Anti-Theft System (PAT .

Push-Button Ignition System Message Center Messages 

The message center provides instruction for operating the push-button ignition system. The message center also displays warnings that indicate a potential concern with the system. These messages pertain to the push-button ignition system:

• PRESS BRAKE TO START - Momentarily displays when the start/stop switch is pressed without the brake pedal being applied.
• ACCESSORY POWER ACTIVE - Displays when the vehicle is in ACC mode.
• SHIFT TO PARK - Displays when the start/stop switch is pressed to shut off the engine with the gear selector lever not in PARK.
• RESTART NOW OR KEY IS NEEDED - Displays when the start/stop switch is pressed to shut the engine off and the IA key is not detected in the vehicle.
• NO KEY DETECTED - Displays if the IA key is not detected by the RFA module while attempting to start the vehicle or enter ACC or RUN mode. If this message is observed with the IA key located inside the vehicle, refer to Anti-Theft Passive Anti-Theft System (PAT .
• STARTING SYSTEM FAULT - Displays if the RFA module receives invalid data from the PCM during PATS authentication. If this message is observed, refer to Symptom Chart: Passive Anti-Theft System (PATS) in Anti-Theft Passive Anti-Theft System (PATS) .