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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Mechanical >> Starter >> Stop And Start System - Circuit Tests & Symptom Tests (3 Of 3) >> Stop And Start System >> After Engine Stops due to Stop and Start System, Engine does not Restart [12/2019 - 10/2022] >> Procedure

After Engine Stops due to Stop and Start System, Engine does not Restart [12/2019 - 10/2022]: Procedure

  1. STOP AND START SYSTEM OPERATION CHECK 
    1. Check if the engine restarts after being stopped by the stop and start system.

      Refer to OPERATION CHECK [12/2019 - ]

      Result

      Result Proceed to
      When the vehicle is stopped, the engine does not restart when attempting to start-off. A
      Engine stall or similar action occurs during idling stop.
      (meter display, etc.)      		 B
      Idling stop continues even when an action* which should restart the engine is performed
      *: Brake pedal is released, the shift lever is operated, etc.      		 C

    Result: 

    B 

    See step  5

    Result: 

    C 

    ENGINE START REQUEST (SYSTEM OF ORIGIN) 

    1. Based on the respective Data List item, troubleshoot the suspected areas which may prevent the ECM from creating engine start requests.

      HINT: 

      Depending on the vehicle, some of the items are not displayed.

      ENGINE START REQUEST (BRAKE RELEASE)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the brakes are operated, inspect the following items:
      • Stop Light switch assembly (ECM)
      • Stop Light switch assembly (ABS/VSC)
      • Master cylinder pressure sensor (brake control system)
      • Stop light switch circuit
      • Airbag sensor assembly (G sensor)

        HINT: 

        Depending on the vehicle, the deceleration sensor may not be built into the airbag sensor assembly, but installed separately.
      • Data List / Stop Light SW (ECM) (OFF: Brake pedal fully released)
      • Data List / Stop Light SW (ABS/VSC) (OFF: Brake pedal fully released)
      • Data List / Master Cylinder Pressure* (Brake pedal released)

        HINT: 

        • *: w/ Vacuum Brake Booster
        • w/o Vacuum Brake Booster: Refer to the threshold of "Driver Operation Control Torque".
      ENGINE START REQUEST (COURTESY SW OR BUCKLE SW) / NUMBER OF ENGINE START REQUEST (DRIVER SIDE BUCKLE) / NUMBER OF ENGINE START REQUEST (DRIVER DOOR)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the driver exited the vehicle, inspect the following items:
      • Driver side seat belt buckle switch circuit (DTC U0140-87 (Lost communication with (main body ECU (multiplex network body ECU))
      • Front seat inner belt assembly (for driver side)
      • Driver side door courtesy switch circuit (DTC U0140-87 (Lost communication with main body ECU (multiplex network body ECU))
      • Driver door courtesy switch circuit
      • Data List / Driver Courtesy Switch Signal (ON: Driver side door open)
      • The driver seat belt is unfastened.
      ENGINE START REQUEST (SHIFT LEVER)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the shift lever is moved, inspect the following items:
      • Shift lever assembly
      • ECM (or transmission control ECU)
      		 Data List / Shift Position
      (Other than D or P)
      ENGINE START REQUEST (CANCEL SW)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the stop and start system cancel switch (ecorun cancel switch assembly) is pushed, inspect the following items:
      • Stop and start system cancel switch (ecorun cancel switch assembly) circuit
      		 Data List / Stop&Start Cancel Switch
      (ON: Stop and start system cancel switch (ecorun cancel switch assembly) pressed)
      ENGINE START REQUEST (STEERING)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the steering wheel is operated, inspect the following items:
      • Steering sensor
      • Steering system
      • Engine stop and start ECU
      		 Data List / Steering Angle
      (The steering wheel is turned 25 deg or more since the engine was stopped by the stop and start system.)
      ENGINE START REQUEST (CLUTCH PEDAL ON)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the clutch pedal is depressed, inspect the following items:
      • Clutch upper switch
      • Engine stop and start ECU
      		 OFF: Clutch pedal depressed
      ENGINE START REQUEST (CLUTCH LOWER SWITCH ON)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the clutch pedal is fully depressed, inspect the following items:
      • Clutch lower switch
      • Engine stop and start ECU
      		 ON: Clutch pedal depressed
      ENGINE START REQUEST (A/C) / ENGINE START REQUEST (A/C 2)

      Action to be Taken and Suspected Area Conditions
      • Check that the stop and start operation conditions related to the air conditioning system are met.
      • When the engine is stopped by the stop and start system and an engine start request is not generated even though all conditions for the air conditioning system to generate a start request are met, inspect the following items:
        1. - Air conditioning system
      • Timer in the air conditioning amplifier assembly runs out
      • Both of the following conditions are met:
        • Blower switch: ON
        • Evaporator temperature exceeds threshold value (threshold value varies with temperature, humidity and amount of solar radiation)
      • Any of the following conditions are met:
        • Blower Switch: ON, and A/C switch: OFF to ON
        • Defogger switch: OFF to ON
        • Blower switch turned off during auto control or blower mode changed to manual
        • Changes from stop and start system priority control to normal system control
      ENGINE START REQUEST (ACCELERATOR)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the accelerator pedal is depressed, inspect the following items:
      • Accelerator pedal sensor assembly
      • ECM (or transmission control ECU)
      		 Data List / Idle
      (OFF: Accelerator pedal depressed)
      ENGINE START REQUEST (BRAKE NEGATIVE PRESSURE LOW)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the brake pedal is further depressed or the brake pedal is pumped, inspect the following items:
      • Brake booster vacuum insufficient
      • Vacuum sensor assembly
      • Brake booster assembly
      • Master cylinder pressure sensor (brake control system)
      • Engine stop and start ECU
      		 Data List / Brake Boost Pressure
      (Brake booster vacuum insufficient (Under 37.5 kPa (0.38 kg/cm2 , 5.4 psi)) (Brake booster vacuum changes in accordance with brake fluid pressure (brake pedal effort))
      ENGINE START REQUEST (IG SWITCH)

      Action to be Taken and Suspected Area Conditions
      When the engine is stopped by the stop and start system and an engine start request is not generated even though the ignition switch or engine switch is operated, inspect the following items:
      • Certification ECU (smart key ECU assembly)*1
      • Engine switch*1
      • Ignition or starter switch assembly*2
      • Engine stop and start ECU
      1. *1: w/ Smart Entry and Start System
      2. *2: w/o Smart Entry and Start System
      		 Starter operating
      • When Data List "Starter Type" is "Tandem Starter":
        • Data List / Starter Motor (ON: Cranking)
        • Data List / Pinion Gear (ON: Starter pinion operating)
      • When Data List "Starter Type" is "Other than Tandem Starter":
        1. Data List / Starter (ON: Starter operating)
      ENGINE START REQUEST (SHIFT P POSITION AND BRAKE)

      Action to be Taken and Suspected Area Conditions
      When the shift lever is in P, the engine is stopped by the stop and start system, and an engine start request is not generated even though the brake pedal is depressed, inspect the following items:
      • Shift lever assembly
      • Stop light switch circuit
      • ECM (or transmission control ECU)
      • Engine stop and start ECU
      • Skid control ECU (brake actuator assembly)
      • Data List / Stop&Start of Engine State (Stop: Engine stopped (by stop and start control))
      • Data List / Shift Position (P)
      • Data List / Stop Light SW (ABS/VSC) (ON: Brake pedal depressed → OFF: Brake pedal released → ON: Brake pedal depressed)
      • Data List / Stop Light SW (ECM) (ON: Brake pedal depressed → OFF: Brake pedal released → ON: Brake pedal depressed)
      • Data List / Master Cylinder Pressure* (40 kPa (0.4 kgf/cm2 , 6 psi) or higher)

        HINT: 

        • *: w/ Vacuum Brake Booster
        • w/o Vacuum Brake Booster: Refer to the threshold of "Driver Operation Control Torque".
      ENGINE START REQUEST (ACC)

      Action to be Taken and Suspected Area Conditions
      When the preceding vehicle has started off but the respective Data List item indicates OFF, inspect the following items:
      • Dynamic radar cruise control system
      • Engine stop and start ECU
      • When the dynamic radar cruise control (w/ full speed range following function) system is operating and the vehicle is stopped, the vehicle is restarted or the preceding vehicle starts off.
      • Operation of the stop and start system is prohibited due to the dynamic radar cruise control system.
      ENGINE START REQUEST (AIR SUSPENSION)

      Action to be Taken and Suspected Area Conditions
      When the air suspension system or side left up seat system is being operated but the respective Data List item indicates OFF, inspect the following items:
      • Air suspension system
      • Side left up seat system
      		 Operation of the stop and start system is prohibited due to the side left up seat system.
      ENGINE START REQUEST (IPA)

      Action to be Taken and Suspected Area Conditions
      When the intelligent parking assist system is being operated but the respective Data List item indicates OFF, inspect the following items:
      • Intelligent parking assist system
      • Engine stop and start ECU
      		 Operation of the stop and start system is prohibited due to the intelligent parking assist system.
      ENGINE START REQUEST (WELCAB)

      Action to be Taken and Suspected Area Conditions
      When the side left up seat system is being operated but the respective Data List item indicates OFF, inspect the following items:
      • Side left up seat system
      		 Operation of the stop and start system is prohibited due to the side left up seat system.
      ENGINE START REQUEST (4WD AND REAR DIFFERENTIAL LOCK)

      Action to be Taken and Suspected Area Conditions
      When drive mode is being operated but the respective Data List item indicates OFF, inspect the following items:
      • Rear differential lock
      • Drive mode
      • Snow mode
      • Data List / Rear Differential Lock Operation State (ON: Lock)
      • Other than COMFORT, ECO or NORMAL mode
      • ON: Snow mode on

    Result: 

    A 

    See step  2

  2. CHECK FOR DTC 
    1. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTC P1603-00 is output A
      DTC P1603-00 is not output B

    Result: 

    A 

    GO TO DTC P1603-00. Refer to  DTC P1603-00: Engine Stall History [12/2019 - 10/2022] 

    Result: 

    B 

    See step  3

  3. CHECK ENGINE CRANKING (WHEN RESTARTING) 
    1. Check if starter motor operation sounds can be heard after the engine is stopped by the stop and start system.

      Result

      Result Proceed to
      Starter motor operation sounds can be heard (for less than 3 seconds)*1 A
      Starter motor operation sounds can be heard (for 3 seconds or more)*2 B
      Starter motor operation sounds cannot be heard*3 C

      HINT: 

      • *1: After combustion occurs, the engine stalls due to insufficient engine speed.
      • *2: The engine continues to crank due to abnormal combustion.
      • *3: The starter motor does not operate.

    Result: 

    A 

    GO TO ENGINE STALLS (SFI SYSTEM). Refer to  Engine Stalls [12/2019 - 10/2022] 

    Result: 

    C 

    GO TO STARTER SIGNAL CIRCUIT. Refer to  Starter Signal Circuit [12/2019 - 10/2022] 

    Result: 

    B 

    See step  4

  4. CHECK ENGINE CRANKING (INITIAL COMBUSTION) 
    1. Confirm if initial combustion occurs during cranking.

      Result

      Result Proceed to
      Initial combustion occurs during cranking but the engine fails to start A
      Initial combustion does not occur during cranking B

    Result: 

    A 

    GO TO SFI SYSTEM 

    Result: 

    B 

    GO TO ENGINE DIFFICULT TO START (SFI SYSTEM). Refer to  Engine Difficult to Start [12/2019 - 10/2022] 

  5. CHECK FOR DTC 
    1. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTC P1603-00 is output A
      DTC P1603-00 is not output B

    Result: 

    A 

    CHECK FREEZE FRAME DATA 

    1. Check the Freeze Frame Data recorded at the time the DTCs were stored.

      Result

      Tester Display Result Suspected Cause Action to be Taken
      Engine Stall History during S&S (Hood Open) ON Engine hood was opened during idling stop Refer to "Engine Hood Courtesy Switch Circuit"
      Refer to Engine Hood Courtesy Switch Circuit [12/2019 - 10/2022]
      Engine Stall History during S&S (Collision or Battery Voltage Low) ON A collision or low battery voltage was detected during idling stop Refer to the troubleshooting procedure for DTC P1603-00 (from step 7).
      Refer to PROCEDURE - Step 7

    Result: 

    B 

    GO TO ENGINE STALLS (SFI SYSTEM) 

    Refer to Engine Stalls [12/2019 - 10/2022]

    HINT: 

    If engine stall is not due to the SFI system, the cause may be due to an unstable power source to the engine stop and start ECU.

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