Description and Operation

Description

System Overview. The system provides the following functions:

• Human-machine interface using a single-stage button to switch terminals and start the engine.
• Control of external relays to switch the ACC / IGN1 / IGN2 and STARTER terminals without using a mechanical ignition switch.
• Vehicle status indication on the LCD display or clear messages on the display.
• Immobilizer function via LF transponder communication between the key fob and the Start/Stop button.
• Redundant architecture for high system reliability.
• Interface with the vehicle Low Speed CAN communication network.
• Interface with the vehicle LIN communication network, depending on platform.

The RKE and SMART KEY functions are not considered part of the engine start/stop button system and are specified in a separate system. Main function of the system

• Switching of ACC/IGN1/IGN2 terminals.
• Control of the STARTER relay BAT line (high side) based on communication with the EMS ECU.
• Control of the immobilizer function.
• Control of the BES warning function.

Push Button Start System: The push button start system allows the driver to operate the vehicle by simply pressing a button (called the SSB) instead of using a conventional mechanical key. When the driver presses the SSB, after smart key authentication, if the brake pedal signal and the shift lever (P) signal are received correctly, the SMK system will unlock the steering column, control the terminal and turn on READY mode. The driver can release the SSB as soon as this sequence is initiated. After a positive response from immobilizer authentication, the system communicates with the VCU, turns on the READY indicator and places the vehicle in "ready" mode for driving. The driver can turn off the EV by pressing the SSB button once while at rest or with the shift lever in P or N. An emergency engine stop can be performed by pressing and holding the SSB button or pressing it 3 times in succession while the vehicle is in READY mode. If the SSB is pressed or a valid fob is confirmed during detection, the system unlocks the steering column and switches the terminals to IGN. In this case, one more press of the SSB is required to enter READY mode. For vehicles equipped with SMART KEY, fob authentication does not require any action from the driver. For a jump start or for a vehicle without SMART KEY, the driver must press the start/stop button.

• Control of ignition and engine start/stop by sending a signal to the IPM.
• Status indication by ON/OFF LED lamp (reddish-orange or amber).

Indicator ON/OFF status when the ignition button is off

No.	Indicator lamp	Conditions
1	Indicator lamp is on	Door open, tail lamp on, ACC, IG on
2	Indicator lamp on for 30 sec. > lamp off	Door closed, tail lamp off, ignition off
3	Indicator lamp off	Remote LOCK, passive LOCK
4	Tail lamp dimmer rheostat (illumination lamp)

Indicator ON/OFF status according to ignition

No.	Ignition conditions	Start button indicator status
1	IG OFF	LED is off
2	IG ACC	LED is yellow
3	IGNITION ON (engine off)	LED illuminates in reddish-orange color.
4	Cranking	Maintain LED status before start
5	Engine is running	LED is off

Wireless Communication. Electromagnetic waves are used to exchange information between the vehicle and the FOB. Two types of RKE key may be complementary to the BES system:

• Non-Smart Key RKE
• SMART KEY FOB

Currently, all BES systems consist of the SMART KEY FOB. The transmitter, receiver and antennas required for communication between the fob and the vehicle vary depending on function and regional specifications. RKE and SMART KEY functions are described in separate documents. For more detailed information on SMART KEY, refer to the Smart Key System section. The SMK smart key controls all functions related to:

• "Start-stop button (SSB) monitoring",
• Immobilizer communication (with the vehicle control unit to unlock the immobilizer),
• ESCL control,
• "Authentication server" (transponder validity and, in the case of the Smart Key option, Passive Fob authentication),
• "System consistency check",
• "System diagnostics",
• Control of message display / warning buzzer.

The unit acts as the master for the entire system. When using SMART KEY, for example, Passive Entry, Passive Lock and Passive Authentication, it is integrated for ESCL/terminal switching operations. It collects vehicle status information from other modules (for example, vehicle speed, alarm status, driver's door open, etc.), reads inputs (for example, SSB, lock button and PARK position switch), controls outputs (for example, exterior and interior antennas), and communicates with other devices via the CAN network and one LIN interface. The SMK also performs diagnostics and learning of the BES system components. Transponder

Starter Terminals and Relays. Relays are used to switch between the ACC/IGN1/IGN2 terminals. Normally open relays are controlled by the SMK unit and are located either in the passenger compartment or in the engine compartment depending on the vehicle architecture. Only one relay coil is connected to the SMK unit terminal outputs. These relays must be integrated with a resistor connected in parallel with the coil to reduce transients during communication. Start/Stop Button (SSB) The one-step button is used by the driver to control the vehicle. By pressing this button, the driver can:

• Switch between the respective terminals to operate in the OFF, ACC, ON and START power modes.
• Enter READY mode
• Turn off the electric vehicle

The backlight is built in to illuminate the button so that the driver can easily find it. Two-color (2) LED lamps located in the center of the button indicate the system status. Another backlight LED is integrated into the SSB to indicate the engine start/stop status.

BES System State Diagram. SYSTEM STATES IN LEARNING MODE. In learning mode, the BES system can be set to 6 different states, depending on the state of the terminals and the engine:

System Status	Terminal status	Engine Status
1. OFF — locked	OFF	Stopped
2. OFF — unlocked	OFF	Stopped
3. ACC	ACC	Stopped
4. IGN	IGN1, IGN2, ACC	Stopped
5. START	IGN1, START	Cranking
6. IGNITION - Engine	IGN1, IGN2, ACC	Run (means "self-sustaining")

Regarding the terminals, the system states described in the tables above are the same as in a system based on a mechanical ignition switch. One difference from a mechanical ignition switch based system is that the BES system allows a specific transition from [OFF] to [START] without passing through the [ACC] and [IGN] states. SYSTEM STATES IN VIRGIN MODE. The BES system can be set to 5 different states (OFF, LOCK. not available in virgin mode), depending on the terminal state and engine state:

System Status	Terminal status	Engine Status
1. OFF - UNLOCKED	OFF	Stopped
2. ACC	ACC	Stopped
3. IGN	IGN1, IGN2, ACC	Stopped
4. Start	IGN1, START with special activation pattern, refer to chapter 6.2.1 for details.	Cranking
5. IGNITION - Engine	IGN1, IGN2, ACC	Run (means "self-sustaining")

Regarding the terminals, the system states described in the tables above are the same as in a system based on a mechanical ignition switch. One difference from a mechanical ignition switch based system is that the BES system allows a specific transition from [OFF] to [START] without passing through the [ACC] and [IGN] states.