System Description

1. The push-button start uses a push-type power switch, which the driver can operate by merely carrying the key. This system consists primarily of the main body ECU, power switch, ID code box (immobiliser code ECU), steering lock ECU (steering lock actuator assembly), electrical key transmitter sub-assembly, ACC relay, IG1 relay, integration relay (IG2 relay) and certification ECU (ECU aggregation box assembly). The main body ECU controls the system. This function operates in cooperation with the smart key system. The table below shows the transition of the power switch state, which depends on whether the brake pedal is depressed or released.
2. This system has different power source mode patterns depending on the brake pedal condition.

   Brake Pedal	Shift State	Power Source Mode Pattern
   Not depressed	P	Each time power switch is pushed off → on (ACC) → on (IG) → off
   		When power switch is pushed in EV system started condition on (READY) → off
   Depressed	P	When power switch is pushed once off → on (READY)
   		When power switch is pushed in on (ACC) condition on (ACC) → on (READY)
   		When power switch is pushed in on (IG) condition on (IG) → on (READY)
   Depressed	Except P	When power switch is pushed in EV system started condition on (READY) → off

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

   HINT: 

   While the vehicle is being driven normally, operation of the power switch is disabled. However, if the EV system must be stopped in an emergency while the vehicle is being driven, pressing and holding the power switch for 2 seconds or more or by quickly pressing the power switch 3 times or more stops the EV system and then the power source mode changes from start to on (ACC).

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

Fig 1: Identifying Powerswitch

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Power switch:

   The power switch consists of a momentary type switch, 2 colored LED (amber, green) and the transponder key amplifier.

   • The amber LED is for illumination.
   • The amber and green LEDs are for the indicator light. The driver can check the present power source mode and whether the EV system can start the illumination state of the indicator light.
   • When the main body ECU detects an abnormality in the smart key system, it makes the amber indicator light flash. If the EV system stops in this state, it might not be possible to restart it.
   TEXT IN ILLUSTRATION
   
   

   *1	Power Switch
   *2	Indicator Light

2. Indicator light condition:
   POWER SWITCH INDICATOR LIGHT CONDITION
   
   

   Power Source Mode/Condition	Indicator Light Condition
   	Brake Pedal Released	Brake Pedal Depressed and Park (P) Selected
   Off	Off	Illuminates (green)
   On (ACC) or on (IG)	Illuminates (amber)	Illuminates (green)
   On (READY)	Off	Off
   Steering lock locked	Flashes (green) for 30 seconds	Flashes (green) for 30 seconds
   System malfunction	Flashes (amber) for 15 seconds	Flashes (amber) for 15 seconds
   Stop light switch malfunction with park (P) selected	Flashes (green) for 15 seconds	Flashes (green) for 15 seconds

3. Main body ECU:

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

Fig 2: Identifying Key Placement

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. To operate the push-button start function when the key battery is low, touch the TOYOTA mark of the key to the power switch while depressing the brake pedal with park (P) selected.
2. The main body ECU transmits a key verification request signal from the stop light switch to the certification ECU (ECU aggregation box assembly).
3. The certification ECU (ECU aggregation box assembly) does not receive an ID code response from the door control receiver, so it actuates the transponder key amplifier built into the power switch.
4. The transponder key amplifier outputs an immobiliser 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 (ECU aggregation box assembly).
7. The certification ECU (ECU aggregation box assembly) 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, with park (P) selected, if the power switch is pressed within 5 seconds with the brake pedal not depressed and park (P) selected, the power source mode changes to on (ACC) or on (IG), which is the same as under normal operation.

The main body ECU can detect malfunctions in the push-button 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 the 5-digit DTC (Diagnostic Trouble Code) in memory.

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