Push Button Start System: Notes

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The push button start system uses the following components to achieve the 4 ignition modes:

Body Control Module (BCM)
Brake Pedal Position (BPP)
Intelligent Access (IA) key
Remote Function Actuator (RFA) module
Start/stop switch

The start/stop switch is a dual contact, normally open switch. The start/stop switch uses 2 sets of internal contacts for redundancy. The contacts are closed when the switch is pressed. The start/stop switch also has 2 LEDs, one LED is used for switch illumination and the other is used to indicate ignition mode. The mode indicator LED only illuminates when the vehicle is in RUN or START mode, it does not illuminate in ACC mode.

To achieve any ignition mode other than OFF, the IA key must be present inside the vehicle. The driver need not perform any actions on the IA key to operate the push button start 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 triggers radio frequency communication between the IA key and the RFA module. If the IA key is not present when the start/stop switch is pressed, the push button start system will not transition from OFF mode and NO KEY DETECTED will be displayed in the message center.

Once communication between the IA key and the RFA module is established, the RFA module sends a message over the Medium Speed Controller Area Network (MS-CAN) to the BCM indicating the correct IA key is present. The BCM then takes the appropriate action based on the start/stop switch and BPP switch inputs.