System Description

1. The push-button start function uses a push-type power switch, which the driver can operate by merely carrying the electrical key. This system consists primarily of the main body ECU, power switch, ID code box, steering lock ECU, electrical key, ACC relay, IG1 relay, IG2 relay and certification ECU. The main body ECU controls the function. This function operates in cooperation with the smart key system.

The electric controls of the push-button start function are described below:

1. Power Switch

   The power switch consists of a momentary type switch, 3 color (amber, green, greenish white) LEDs, and a transponder key amplifier.

   • The greenish white LED is for illumination.
   • The amber and green LEDs are for the indicator lights. The driver can check the present power source mode and whether the HV control system can start in accordance with the illumination state of the indicator light.
   • When the main body ECU detects an abnormality in the push-button start function, it makes the amber indicator light flash. If the HV control system stopped in this state, it may not be possible to restart it.
   Fig 1: Identifying Engine Indicator Light

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Indicator Light Condition

   Power switch indicator light condition: 

   POWER SWITCH INDICATOR LIGHT CONDITION CHART
   
   

   Power Source Mode/Condition	Indicator Light Condition
   	Brake pedal released	Brake pedal depressed, shift lever in P
   off	OFF	ON (Green) (when key and vehicle IDs match)
   on (ACC, IG)	ON (Amber)	ON (Green)
   HV control system on (READY)	OFF	OFF
   Steering lock not unlocked	Flashes (Green) for 15 sec.	Flashes (Green) for 15 sec.
   System malfunction	Flashes (Amber) for 15 sec.	Flashes (Amber) for 15 sec.

3. Main body ECU

   The main body ECU consists of the IG1 and IG2 relay actuation circuits and CPU.

   HINT:

   Before removing the battery, make sure to turn the power switch off. The main body ECU constantly stores the present power source mode in its memory. Therefore, if the main body ECU is interrupted by disconnecting the battery, the main body ECU restores the power source mode after the battery is reconnected. For this reason, if the battery is disconnected when the power switch is not off, the power will be restored to the vehicle at the same time the power is restored to the main body ECU (by reconnecting the battery).

1. This system has different power source mode patterns depending on the brake pedal condition and shift lever position.
   BRAKE PEDAL CONDITION AND SHIFT LEVER POSITION REFERENCE
   
   

   Brake Pedal	Shift Lever	Power Source Mode Pattern
   Depressed	P position	When the power switch is pushed once. off → HV control system on (READY) on (ACC) → HV control system on (READY) on (IG) → HV control system on (READY)
   Not depressed	P position	Each time the power switch is pushed. off → on (ACC) → on (IG) → off
   	Except P position	Each time the power switch is pushed. off → on (ACC) → on (IG) → on (ACC)
   -	P position	When the power switch is pushed with power source mode on (READY). HV control system on (READY) → off
   -	Except P position	When the power switch is pushed with power source mode on (READY). HV control system on (READY) → on (ACC)

   When the battery of the key is low, the push-button start function can be operated by holding the key against the power switch.

• After approximately 1 hour has passed with the power switch on (ACC) and the shift position in P, the main body ECU will automatically cut the power supply (the power source mode changes to off).
• The illustration below shows the transition of power source modes.

  Transition of power source mode:

  Fig 2: Transition Of Power Source Mode Chart

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  HINT:

  While the vehicle is being driven normally, operation of the power switch is disabled. However, if the HV control system must be stopped in an emergency while the vehicle is being driven, pressing the power switch for 3 seconds or more stops the HV control system. Power source mode changes from on (READY) to on (ACC).

1. To operate the push-button start function when the key battery is low, hold the key close to the power switch with the brake pedal depressed.
2. The main body ECU transmits a key verification request signal from the stop light switch to the certification ECU.
3. The certification ECU does not receive an ID code response from the entry door control receiver, so it actuates the transponder key amplifier built into the power switch.
4. The transponder key amplifier outputs an engine immobilizer radio wave to the key.
5. The key receives the radio wave, and returns a radio wave response to the transponder key amplifier.
6. The transponder key amplifier combines the key ID codes with the radio wave response, and transmits it to the certification ECU.
7. The certification ECU judges and verifies the ID code, and transmits a key verification OK signal to the main body ECU. The buzzer in the combination meter sounds at the same time.
8. After the buzzer sounds, if the power switch is pressed within 5 seconds with the brake pedal not depressed, the power source mode changes to on (ACC) or on (IG), the same as in the normal condition.
   Fig 3: Identifying Power Switch Dimension

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The main body ECU can detect malfunctions in the pushbutton start function when the power source mode is on (IG). When the ECU detects a malfunction, the amber indicator light of the power switch flashes to warn the driver. At the same time, the ECU stores a 5-digit DTC (Diagnostic Trouble Code) in the memory.

• The indicator light warning continues for 15 seconds even after the power source mode is changed to off.
• The DTC can be read by connecting Techstream to the DLC3.
• The push-button start function cannot be operated if a malfunction occurs.