Starting: Other Lexus LS IV

PRECAUTION

Note. When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected.

SYSTEM REFERENCE

1. EMERGENCY ENGINE START CONTROL If there is a malfunction in the stop light switch or STOP fuse, their signals may not be correctly transmitted to the main body ECU. This may result in the engine not starting even if the engine switch is pressed while the brake pedal is depressed and the shift lever is in the P position. To activate the starter: Turn the engine switch from off to on (ACC). Press and hold the engine switch for 15 seconds.
2. PRECAUTIONS FOR PUSH-BUTTON START FUNCTION: Before starting the engine, firmly depress the brake pedal until the indicator in the engine switch turns green. The power source mode (off, on (ACC), on (IG)) is always retained in the memory by the vehicle. If the battery is disconnected, the power source mode that was present before the disconnection will be restored after the battery is reconnected. Be sure to turn the engine switch off before disconnecting the cable from the negative battery terminal. Be careful if the power source mode of a vehicle with a discharged battery is not known. After the battery is reconnected, be sure to wait 10 seconds or more before attempting to start the engine. The engine may not start immediately after the battery is reconnected. If the LEXUS mark of the key or card key is touched to the engine switch to start the engine when the key or card key battery is depleted or affected by wave noise, etc., the following warnings will sound: Driver's door open --> closed An exit warning will sound if the shift lever is in a position other than P and the power source is in a mode other than off. An exit warning will sound if the shift lever is in the P position and the power source is in a mode other than off. Doors other than the driver door open --> closed A warning will sound to indicate that the key or card key has been taken out of the vehicle. These warnings will sound because it is not possible for the vehicle to determine if the key or card key is present in the vehicle (due to the depleted key battery). These warnings do not indicate system malfunctions.

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Communication table

COMMUNICATION CHART

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1. PUSH-BUTTON START DESCRIPTION The push-button start uses a push-type engine switch, which the driver can operate by merely carrying the key. This system consists primarily of the main body ECU, engine switch, ID code box, steering lock ECU, key, D-ACC relay, D-IG1 relay, IG2 relay and certification ECU. The main body ECU controls the system. This function operates in cooperation with the smart access system with push-button start. The table below shows the transition of the engine switch, which depends on whether the brake pedal is depressed or released. This system has different power source mode patterns depending on the brake pedal and shift lever conditions. SYSTEM DESCRIPTION Condition Power Source Mode Pattern Brake pedal not depressed, shift lever in P Each time engine switch is pushed off --> on (ACC) --> on (IG) --> off Brake pedal not depressed When engine switch is pushed in engine started condition Engine started --> off Brake pedal depressed, shift lever in P or N When engine switch is pushed once off --> engine start Brake pedal depressed, shift lever in P or N When engine switch is pushed in on (ACC) condition on (ACC) --> engine start Brake pedal depressed, shift lever in P or N When engine switch is pushed in on (IG) condition on (IG) --> engine start Brake pedal depressed When engine switch is pushed in engine started condition Engine started --> off When the battery of the key or card key is low, the push-button start function can be operated by touching the key or card key to the engine switch.
2. FUNCTION OF COMPONENT COMPONENT FUNCTION CHART Components Function Engine Switch (Transponder Key Amplifier) Transmits engine switch signal to main body ECU. Informs driver of power source mode or system abnormality with indicator light illumination. Receives ID code and transmits it to certification ECU when key or card key battery is low or affected by wave noise, etc. Key Receives signals from oscillators and returns ID code to entry door control receiver. Indoor Key Oscillator Receives request signal from certification ECU and forms detection area in vehicle interior. Door Control Receiver Receives ID code from key and transmits it to certification ECU. Main Body ECU Changes power source mode in 4 stages (off, on (ACC), on (IG), start) in accordance with state of park/neutral position switch. Controls push-button start function in accordance with signals received from switches and each ECU. Certification ECU Certifies ID code received from entry door control receiver and transmits certification results to ID code box and steering lock ECU. Park/Neutral Position Switch Outputs state of shift position to main body ECU. Stop Light Switch Outputs state of brake pedal to main body ECU. ID Code Box Receives steering unlock or engine immobilizer unset signals from certification ECU, certifies them, and transmits each unset signal to steering lock ECU or ECM. ECM Receives engine start request signal from power source control ECU, turns ON ST relay, and starts engine. Receives signal from ID code box and performs engine ignition and fuel injection.
3. SYSTEM FUNCTION The electric controls of the push-button start function are described below: SYSTEM FUNCTION Control Outline Engine Switch Control When driver operates engine switch with key in driver's possession, certification ECU starts indoor key oscillator, which transmits request signal to key. Upon receiving this signal, key transmits ID code signal to door control receiver. ID code box verifies check results received from certification ECU via LIN line and sends them to main body ECU. Based on these results, main body ECU authorizes operation of engine switch. Diagnosis When main body ECU detects malfunction, main body ECU diagnoses and memorizes failed section.
4. CONSTRUCTION AND OPERATION Engine switch: The engine switch consists of a momentary type switch, color (amber, green) LEDs, and transponder key amplifier. The amber 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 or not in accordance with the illumination state of the indicator light. When the main body ECU detects an abnormality in the smart access system with push-button start, it makes the amber indicator light flash. If the engine is stopped in this state, it might not be possible to restart it. Indicator light condition: Engine switch indicator light condition POWER SOURCE MODE CHART Power Source Mode/Condition Indicator Light Condition Brake pedal released Brake pedal depressed, shift lever in P or N Off OFF Illuminates (green) On (ACC, IG) Illuminates (amber) Illuminates (green) Engine running OFF OFF Steering lock not unlocked 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 with shift lever in P or N malfunction Flashes (green) for 15 seconds Flashes (green) for 15 seconds Main body ECU: The main body ECU consists of the D-IG1 relay, D-ACC relay and IG2 relay actuation circuits and CPU.
5. SYSTEM NOT OPERATING NORMALLY (DUE TO KEY BATTERY DEPLETION, ELECTRICAL NOISE, ETC.) To operate the push-button start function when the key or card key battery is low or affected by wave noise, etc., touch the LEXUS mark of the key or card key to the engine switch while depressing the brake pedal with the shift lever in P or N. The main body ECU transmits a key verification request signal from the stop light switch to the certification ECU. The certification ECU does not receive an ID code response from the door control receiver, so it actuates the transponder key amplifier built into the engine switch. The transponder key amplifier outputs an engine immobilizer 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. 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. After the buzzer sounds, with the shift lever in P or N, if the engine switch is pressed within 10 seconds with the brake pedal not depressed, the power source mode changes to on (ACC) or on (IG), as in the normal condition.
6. DIAGNOSIS 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 engine switch flashes to warn the driver. At the same time, the ECU stores the 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 Techstream to the DLC3. The push-button start function cannot be operated if a malfunction occurs.

CUSTOMIZE PARAMETERS

1. CUSTOMIZING FUNCTION WITH TECHSTREAM (REFERENCE) NOTE: When the customer requests a change in a function, first make sure that the function can be customized. Be sure to make a note of the current settings before customizing. When troubleshooting a function, first make sure that the function is set to the default setting. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Customize Setting. Select the setting by referring to the table below. Smart Key/Access SMART KEY/ACCESS CHART Display Default Contents Setting Ignition Available Area All Function to choose the available area for key to start engine and cancel the steering lock. Front/All