Description and Operation

Description

GENERAL DESCRIPTION OF THE SYSTEM The system has the following features:

• The driver interacts with the system using the one-step button to change the terminal and start the engine.
• Control of external relays to switch the ACC/ALL1/ALL2 terminals and STARTER without using a mechanical ignition switch.
• Steering column locking by the ESCL unit, checking vehicle status to ensure safe ESCL activation.
• Vehicle status indication by LEDs or explicit messages.
• Immobilizer function through AvG 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 the platform.

The RKE and SMK functions are not considered part of this engine start button system and are specified in a separate system. Main function of the system

• Steering column lock/unlock by ESCL.
• Switching of ACC/ALL1/ALL2 terminals.
• Control of the BAT (high side) line of the STARTER relay based on communication with the EMS ECU.
• Control of the immobilizer function.
• Control of the BES warning function.

Engine Start Button System The start button system allows the driver to operate the vehicle by simply pressing the button (called SSB) instead of using a conventional mechanical key. It also controls locking and unlocking of the steering column (called ESCL) without any special action by the driver. If the driver presses the SSB with the brake pedal applied, smart key authentication and status transmission are performed, and the BCM performs steering column locking/unlocking, gear selection control, and engine start. The driver may release the SSB once the sequence is initiated. After one positive response to the immobilizer request, the system cranks the engine with the starter and communicates with the EMS to monitor the running engine condition and stop the starter. The driver can stop the engine by a short press of the SSB if the vehicle is already stopped. Emergency engine stop is possible by a long press of the SSB or 3 consecutive presses if the vehicle is in RUNNING ENGINE mode. If the engine start conditions are not met when the SSB is pressed and a valid smart key is authenticated, the system unlocks the steering column and changes the terminals to ON: another press of the SSB is required to start the engine. For a vehicle equipped with SMK, key fob authentication requires no action by the driver. For the recovery start mode or for vehicles without SMK, the driver must press the start/stop button.

• Control of ignition and engine start/stop by sending a signal to the IPM.
• Status display by ON/OFF LED indicator (amber or blue).

Indicator ON/OFF Status with Ignition Off

NO	Character indicator	Confirmation
1	Power indicator	Door open, tail lamps on, ACC, ignition on
2	Indicator lamp ON for 30 sec → Lamp OFF	Door closed, tail lamps off, ignition off
3	Indicator OFF	Remote LOCK, passive LOCK
4	Tail lamp dimmer on (illumination indicator)

ON/OFF Indicator Status by Ignition Key Position

NO	Ignition conditions	Power button indicator status
1	Ignition off	LED is off
2	ALL ACC	Yellow LED on
3	IGNITION ON (engine off)	Blue LED on
4	Starting	Hold LED status before starting
5	ENGINE RUNNING	LED is off

Operation for Each Start Button Function

1. 1
   Power on / ignition on

   • The power supply undergoes the following changes: OFF → ACC → IGN → OFF by pressing the button without pressing the brake (or pressing the brake) inside the vehicle with the key fob (however, repeat ACC↔IGN when speed is not in P. Switching to OFF is not possible.)
   • Start is initiated by pressing the button while pressing the brake in the P/N position with the key fob.

   

2. 2
   Power off / ignition off

   • Ignition off is possible when the vehicle is stationary. (Ignition off is possible in any Selector lever position.)
   • The lever will be held in N, and to park, press the lever release button after turning the ignition to OFF.

   

3. 3
   How to forcibly turn off the ignition and restart the engine while driving

   • This is a method of forcibly stopping the vehicle in case of fuel leakage or an emergency (for example, a malfunctioning accelerator pedal return).
   • The engine stops and returns to the ACC state when the button is pressed for 2 seconds or more, 3 times successfully within 3 seconds, while driving. Restart is available within the following 30 seconds regardless of the key fob. The power supply goes through the following transitions: OFF → ACC → IGN → OFF by pressing the button without pressing the brake (or with the brake pressed) inside the vehicle with the key fob. (However, when not in P, ACC↔IGN repeats. Conversion to OFF is not possible.)

   

4. 4
   Brake switch input has a 0.5 second delay function. Starting is possible with the brake pedal pressed 0.5 seconds after pressing the start button with the engine off.
5. 5
   The start button indicator (LED) illuminates according to the power supply status.

   • Power off: LED off
   • ACC power supply status: yellow LED illuminated
   • Power on: blue LED illuminated
   • During start: the previous LED remains illuminated until start
   • Initial ON state: LED OFF

   

RECOVERY DRIVING MODE

• When brake input is not made (AT specification), transition to START when SSB is pressed for more than 10 seconds in the ACC state.
• If there is a communication problem between EMS and CAN (mainly unable to determine EMS status), transition to MOTORCYCLE state from START based on input from the trusted platform module.
• In case of absence of two SSB input lines, power on and off is available by pressing SSB twice within 10 seconds (SSB LIMP HOME PRESS). The buzzer sounds when the button is pressed the first time. Power cycle is available, and the buzzer stops when the button is pressed twice within ten seconds.

Smart Key

SMK controls all functions related to:

• On/Off button (SSB) control,
• Immobilizer communication (with engine control unit to activate immobilizer),
• Authentication server (transponder validity and, in case of authentication, passive key fob option SMK),
• system integrity check,
• system diagnostics,
• Message display/buzzer control

The device acts as the master for the entire system. When SMK functions such as Passive Entry, Passive Lock, and Passive Start are used, they are integrated for ignition switching operations. The Terminal Manager collects vehicle status information from other modules (vehicle speed, alarm status, driver door open, etc.), reads inputs (for example, SSB, capacitive sensor/lock button, PARK position switch), controls outputs (for example, interior and exterior antennas), and communicates with other devices via the CAN network and LIN interfaces. Diagnostics and learning of BES system components are also controlled by SMK. SMK controls functions related to Terminal Control by activating external relays for ACC, ALL 1 and ALL 2. This unit is also responsible for controlling the STARTER relay. SMK also controls SSB illumination and the System Status Indicator, which consists of two LEDs of different colors. Key fob support is also handled by SMK. SMK reads inputs (key fob insertion, vehicle speed, relay contact status), controls outputs (STARTER relay output wires), and communicates with other devices over CAN. The internal architecture of SMK is designed so that terminal control is maintained even if one or two microcontrollers fail, the system becomes inconsistent, or network communication is interrupted. If one or two controllers fail, the remaining controller disables the STARTER relay. Terminal relays ALL1 and ALL2 will be kept in the state they were in until the failure, and the driver can deactivate these ALL terminals by pressing the SSB with the EMERGENCY_STOP press sequence. However, engine restart is not permitted. The state of the ACC relay depends on the type of failure. The main functions of SMK are:

• Terminal control relay
• Check vehicle speed received from the ABS/ESP sensor ECU.
• SSB LED control (on, off)
• Control of the base station located in the SSB via direct serial interface.
• System consistency check to diagnose SMK failure and enter driving recovery mode.
• Provision of vehicle speed information
• On/Off button (SSB) control
• Electric starter control

Start/Stop Button (SSB) A one-step button is used by the driver to operate the vehicle. Pressing this button allows you to:

• Activation of OFF, ACC, ON and START power modes by switching to the corresponding terminals
• Starting the Engine
• Turning Off the Engine

The contact is provided by a microswitch and an emergency lamp is provided to highlight the button marking, if necessary. Two (2) colored LEDs are located in the center of the button to indicate system status. Other LED lighting is also integrated into the SSB to illuminate the engine Start/Stop symbols.

Electronic Steering Column Lock (ESCL) ESCL is required to lock the steering column to prevent unauthorized use of the vehicle. To achieve the full level of security, ESCL is monitored and controlled by SMK. This redundant architecture ensures that the ESCL motor is powered only during the lock/unlock operation and that it is disconnected from battery and ground lines to prevent unintended operation while the vehicle is moving. Data exchange between ESCL and SMK is performed through an encrypted serial communication interface.

BES System State Table. BES SYSTEM STATES IN LEARNING MODE. In learning mode, the BES system can be in 6 different states depending on the status of the terminals, ESCL and engine:

System Status	Terminal status	ESCL status	ENGINE STATUS
1. OFF - locked	OFF	LOCKED	STOP
2. OFF - unlocked	OFF	unlocked	STOP
3. ACC	SOUND	unlocked	STOP
4. ALL	ALL1, ALL2, ACC	unlocked	STOP
5. Start	IGN1, START	unlocked	Starting
6. ALL - engine	ALL1, ALL2, ACC	unlocked	RUNNING (means "rotates alone")

Regarding terminals, the system states are described in the table above. They are the same as for a system based on a mechanical ignition switch. The only difference from a mechanical ignition switch system is that the BES system allows a specific transition from [OFF] to [START] without passing through the [ACC] and [ALL] states. BES SYSTEM STATES IN PRIMARY MODE. The BES system can be set to 5 different states (OFF, LOCKED, if not available in empty mode), depending on the state of the terminals, ESCL and engine:

System Status	Terminal status	ESCL status	ENGINE STATUS
1. OFF - UNLOCKED	OFF	unlocked	STOP
2. ACC	SOUND	unlocked	STOP
3. ALL	ALL1, ALL2, ACC	unlocked	STOP
4. Departure	IGN1, START with special activation model, see section 6.2.1. details	unlocked	Starting
5. ALL - engine	ALL1, ALL2, ACC	unlocked	RUNNING (means "rotates alone")

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