PUSH-BUTTON START DESCRIPTION
The push-button start uses a push-type engine switch, which the driver can operate by merely carrying the electrical key. This system consists primarily of the power source control ECU, engine switch, ID code box (immobiliser code ECU), steering lock ECU, electrical key, ACC relay, IG1 relay, IG2 relay and certification ECU (smart key ECU assembly). The power source control ECU controls the system. This function operates in cooperation with the entry and start system.
FUNCTION OF COMPONENT
| Component | Function |
|---|---|
| Engine Switch
|
|
| Electrical Key | Receives signals from oscillators and returns ID code to entry door control receiver. |
| Electrical Key Oscillator
|
Receives request signals from certification ECU (smart key ECU assembly) and forms detection area in vehicle interior. |
| Entry Door Control Receiver | Receives ID code from electrical key and transmits it to the certification ECU (smart key ECU assembly). |
| Power Source Control ECU |
|
| Certification ECU (smart key ECU assembly) | Certifies the ID code received from entry door control receiver and transmits certification results to the ID code box (Immobiliser Code ECU) and steering lock ECU. |
| Stop Light Switch | Outputs state of brake pedal to power source control ECU. |
| ID Code Box (immobiliser code ECU) | Receives steering unlock or engine immobiliser unset signals from certification ECU (smart key ECU assembly), certifies them, and transmits each unset signal to steering lock ECU or ECM. |
| ECM |
|
SYSTEM FUNCTION
The electric controls of the push-button start function are described below:
| Control | Outline |
|---|---|
| Engine switch control |
|
| Diagnosis | When power source control ECU detects malfunction, the power source control ECU diagnoses and memorizes the failed section. |
CONSTRUCTION AND OPERATION
Engine Switch
The engine 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 engine can start in accordance with the illumination state of the indicator light.
When the power source control ECU detects an abnormality in the push-button start system, it makes the amber indicator light flash. If the engine stopped in this state, it may not be possible to restart it.
Indicator Light Condition
| Power Source Mode/Condition | Indicator Light Condition | |
|---|---|---|
| Brake pedal released | Brake pedal depressed, shift lever in P or N | |
| off | OFF | Turns ON (Green) |
| on (ACC, IG) | Turns ON (Amber) | Turns ON (Green) |
| Engine running | 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. |
Power Source Control ECU
The power Source Control ECU consists of the IG1 and IG2 relay actuation circuits and CPU.
Tech Tips
Before removing the battery, make sure to turn the engine switch off. The power source control ECU constantly stores the present power source mode in its memory. Therefore, if the power source control ECU is interrupted by disconnecting the battery, the power source control ECU restores the power source mode after the battery is reconnected. For this reason, if the battery is disconnected when the engine switch is other than off, the power will be restored to the vehicle at the same time the power is restored to the power source control ECU (by reconnecting the battery).
PUSH-BUTTON START FUNCTION OPERATION
This system has different power source mode patterns depending on the brake pedal condition and shift lever position.
| Brake Pedal | Shift Lever | Power Source Mode Pattern |
|---|---|---|
| Depressed | P or N | When the engine switch is pushed once.
|
| Not depressed | P | Each time the engine switch is pushed.
|
| Except P | Each time the engine switch is pushed.
|
|
| - | P | When the engine switch is pushed in the on (IG) condition (engine running).
|
| - | Except P | When the engine switch is pushed in the on (IG) condition (engine running).
|
When the battery of the key is low, the push-button start function can be operated by holding the key against the engine switch.
After approximately 1 hour has passed with the engine switch on (ACC) and the shift position in P, the power source control 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:
Tech Tips
While the vehicle is being driven normally, operation of the engine switch is disabled. However, if the engine must be stopped in an emergency while the vehicle is being driven, pressing the engine switch for 3 seconds or more stops the engine. Power source mode changes from start to on (ACC).
WHEN KEY BATTERY IS LOW
To operate the push-button start function when the key battery is low, hold the key close to the engine switch with the brake pedal depressed.
The power source control ECU transmits a key verification request signal from the stop light switch to the certification ECU (smart key ECU assembly).
The certification ECU (smart key ECU assembly) does not receive an ID code response from the entry door control receiver, so it actuates the transponder key amplifier built into the engine switch.
The transponder key amplifier outputs an engine immobiliser radio wave to the key.
The key receives the radio wave, and returns a radio wave response to the transponder key amplifier.
The transponder key amplifier combines the key ID codes with the radio wave response, and transmits it to the certification ECU (smart key ECU assembly).
The certification ECU (smart key ECU assembly) judges and verifies the ID code, and transmits a key verification OK signal to the power source control ECU. The buzzer in the combination meter sounds at the same time.
After the buzzer sounds, if the engine 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.
DIAGNOSIS
The power source control 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 engine 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 the intelligent tester to the DLC3.
The push-button start function cannot be operated if a malfunction occurs.