Principles of Operation

Steering Column Switches

Principles of Operation

Ignition Switch

The ignition switch is controlled by the ignition lock cylinder with a key. When the ignition lock cylinder is turned, a mechanical connection positions the ignition switch to the selected position. The available ignition switch positions are:

- OFF
- ACC
- ON
- START

The ignition switch supplies battery voltage to the Central Junction Box (CJB) which then distributes this voltage to multiple circuits and modules throughout the vehicle, based on ignition switch position.

Push Button Start System

The Remote Function Actuator (RFA) module applies battery voltage to the same circuits that a conventional ignition switch uses to achieve 3 of the 4 standard ignition states (OFF, ON and START). Unlike a conventional ignition switch system, this push button start system does not have a driver accessible ACC mode. The RFA module automatically cycles through the ACC mode when the driver cycles the vehicle to the ON mode. The RFA module receives input from the following:

- Clutch Pedal Position (CPP) switch (manual transaxle)
- Cruise control deactivator switch (automatic transaxle)
- Intelligent Access (IA) key (wireless input)
- Park detect switch (automatic transaxle)
- Start/stop switch

The RFA module uses input from the IA key to authorize use of the vehicle. The RFA module uses input from the start/stop switch, the park detect switch (automatic transaxle), the cruise control deactivator switch (automatic transaxle) and/or the CPP switch (manual transaxle) to transition between ignition modes.

Intelligent Access (IA) Key

To achieve any ignition state other than OFF, the IA key must be present inside the vehicle. The driver need not perform any actions with 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.

Backup Antenna

If the battery inside the IA key is weak, if the IA key is damaged or if excessive ambient Radio Frequency Interference (RFI) prevents communication between the RFA module and the IA key, the backup antenna located on the RH side of the steering column (where a conventional ignition lock cylinder would be located) provides a secondary means for the RFA module to validate the IA key and authorize use of the vehicle. The backup antenna uses passive radio frequency identification to exchange signals with the IA key, similar to the way a typical encoded Passive Anti-Theft System (PATS) key and transceiver operate. For additional information on the IA key and backup antenna, refer to Anti-Theft - Passive Anti-Theft System (PATS) Testing and Inspection.

Push Button Start System Front Control/Display Interface Module (FCDIM) Messages

The FCDIM provides instruction for operating the push button start system. The FCDIM can also display warnings that could indicate a potential issue with the push button start system. The following FCDIM messages pertain to the push button start system:

- TO START PRESS BRAKE - Momentarily displays when the start/stop switch is pressed without the brake pedal being applied (vehicles equipped with an automatic transaxle).
- TO START PRESS CLUTCH - Momentarily displays when the start/stop switch is pressed without the clutch pedal being applied (vehicles equipped with a manual transaxle).
- TO START SELECT N OR P - Displays when attempting to start the vehicle and the transaxle is not in NEUTRAL or PARK (vehicles equipped with an automatic transaxle).
- VEHICLE NOT IN PARK SELECT P - Displays when the start/stop switch is pressed to shut off the engine with the transaxle selector lever in any position other than PARK (vehicles equipped with an automatic transaxle).
- KEY OUTSIDE CAR - Whenever a door is opened and then closed while the engine is running, the RFA module searches for the IA key. This message displays if the key is not detected by the module.
- KEY NOT DETECTED - Displays if the IA key is not detected by the RFA module when attempting to enter ON mode or attempting to start the vehicle. If this message is observed with the IA key located inside the vehicle, go to Anti-Theft - Passive Anti-Theft System (PATS) Testing and Inspection to diagnose the IA key.

Remote Function Actuator (RFA) Module Programming

If it is necessary to replace the RFA module, the replacement module must be programmed. Carry out the following scan tool functions if an RFA module is installed new:

NOTE: All of the following scan tool functions must be completed before the vehicle will start.

- Programmable Module Installation (PMI) - This process configures the new module with specific vehicle information. Refer to Programmable Module Installation (PMI) in Module Configuration Programmable Module Installation (PMI).
- PATS Parameter Reset - This process initiates an exchange of information between the RFA module and the PCM specific to the anti-theft/engine immobilizer feature. Carry out a PATS parameter reset when either the RFA module or the PCM is installed new. For additional information, refer to Passive Anti-Theft System (PATS) Parameter Reset-Intelligent Access (IA) in Anti-Theft - Passive Anti-Theft System (PATS) Passive Anti-Theft System (PATS) Parameter Reset.
- IA Key Programming - This process programs the IA keys to the RFA module. If the RFA module is installed new, 2 IA keys will have to be programmed before the vehicle will start. For additional information, refer to Key Programming Using Diagnostic Equipment-Intelligent Access (IA) in Anti-Theft - Passive Anti-Theft System (PATS) Key Programming.

Multifunction Switches

The multifunction switches control the various components (high beam headlamps, flash-to-pass, turn signal, trip computer display and windshield wiper/washer) by grounding certain Body Control Module (BCM) or Instrument Panel Cluster (IPC) circuits. When the BCM or IPC detects the ground signal, voltage is sent to activate the appropriate component. The BCM controls the high beam headlamps, flash-to-pass, turn signals and windshield wipers/washers. The IPC controls the trip computer display.

For multifunction switch concerns, refer to one of the following systems:

- For high beam headlamps, flash-to-pass and turn signal concerns, refer to Exterior Lighting Testing and Inspection and Testing and Inspection.
- For wiper and washer concerns, refer to Wipers and Washers Testing and Inspection.
- For trip computer concerns, refer to Instrumentation, Message Center, and Warning Chimes Testing and Inspection.