STOP AND START SYSTEM, Diagnostic DTC:P323B

DTC Code DTC Name
P323B Backup Boost Converter

DESCRIPTION

Refer to DTC B22C0

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DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
P323B Backup Boost Converter

Any of the following conditions are met for 1 second or more (1 trip detection logic):


  • BBC malfunction is detected

  • Engine stop and start ECU thermistor temperature is 128°C (262.4°F) or higher

  • Difference in temperature between thermistor 1 and thermistor 2 of the engine stop and start ECU is 40°C (104°F) or higher

  • BO1 voltage is 6.0 V or less and BBC is not overheating

  • IGO1 voltage is 6.0 V or less

  • Engine stop and start ECU

  • Wire harness or connector

  • Battery

  • BBC fuse

 Blinks DTC stored

CONFIRMATION DRIVING PATTERN

Tech Tips

DTCs for the stop and start system are not cleared automatically even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.

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  1. Tech Tips


    • If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.

    • Allow the engine to idle for 3 minutes after it is warmed up and check that the engine idle speed is within 50 rpm of the target idle speed.

    CONFIRMATION AFTER TROUBLESHOOTING


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Click here


      Powertrain > Stop and Start > Clear DTCs

    4. Start the engine and warm it up.

    5. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    6. Stop the vehicle, move the shift lever to neutral and release the clutch pedal. (for Manual Transaxle)

    7. Depress the brake pedal and stop the vehicle. (for CVT)

    8. Keep the engine stopped by stop and start control for 1 second or more. (Keep the shift lever in D. (for CVT))

    9. Depress the clutch pedal and start the engine. (for Manual Transaxle)

      Tech Tips

      If the engine cranks slowly when the engine is restarted, it can be determined that the battery voltage is low.

    10. Release the brake pedal with the shift lever in D to start the engine. (for CVT)

      Tech Tips

      If the engine cranks slowly when the engine is restarted, it can be determined that the battery voltage is low.

    11. Check that DTCs are not output.

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      Powertrain > Stop and Start > Trouble Codes

  2. STOP AND START SYSTEM OPERATION CHECK

    Tech Tips

    If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.


    1. Start the engine and warm it up.

    2. Turn the air conditioning system off.

    3. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    4. Stop the vehicle, move the shift lever to neutral and release the clutch pedal. (for Manual Transaxle)

    5. Depress the brake pedal and stop the vehicle. (for CVT)

    6. Allow the engine to stop by stop and start control. (Keep the shift lever in D. (for CVT))

    7. Depress the clutch pedal and start the engine. (for Manual Transaxle)

    8. Release the brake pedal with the shift lever in D to start the engine. (for CVT)

WIRING DIAGRAM

Refer to DTC B22C0.

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CAUTION / NOTICE / HINT

Note


  • Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU.

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  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.

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  • After replacing the engine stop and start ECU or airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

Tech Tips

Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.

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PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BBC FUSE)

    Result
    Proceed to
    OK
    NG

    1. Disconnect the A8 engine stop and start ECU connector.

    2. Remove the BBC fuse from engine room relay block and junction block assembly.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A8-7 (BIN) - BBC fuse terminal 2 Always Below 1 Ω
      A8-7 (BIN) - Body ground Always 10 kΩ or higher
      BBC fuse terminal 2 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU POWER SOURCE CIRCUIT)


    1. A01M04AC04
      *a

      Front view of wire harness connector:

      (to Engine Stop and Start ECU)

      Disconnect the A8 and E24 engine stop and start ECU connectors.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A8-7 (BIN) - Body ground Always 9.5 to 14 V

    3. Turn the ignition switch to ON.

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      E24-17 (IG1) - Body ground Ignition switch ON 9.5 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BODY GROUND)


    1. Disconnect the A8 engine stop and start ECU connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A8-8 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - EACH ECU OR SENSOR)

    Result
    Proceed to
    OK
    NG

    1. Disconnect the E24 engine stop and start ECU connector.

    2. Disconnect the E1 radio and display receiver assembly*1 or E109 radio receiver assembly*2 connector.


      • *1: for Radio and Display Receiver Assembly Type

      • *2: for Radio Receiver Assembly Type

    3. Disconnect the A97 skid control ECU (brake actuator assembly) connector.

    4. Disconnect the E30 power steering ECU assembly connector.

    5. Disconnect the 3C instrument panel junction block assembly (main body ECU (multiplex network body ECU)) connector.

    6. Disconnect the E19 spiral cable with sensor sub-assembly connector.

    7. Disconnect the O3 inner rear view mirror assembly connector.

    8. Disconnect the E98 clearance warning ECU assembly connector*3.

      *3: w/ TOYOTA Parking Assist-Sensor System

    9. Disconnect the L70*4, L88*5 or Q15*6 tire pressure monitor receiver assembly connector.


      • *4: for Sedan

      • *5: for Hatchback

      • *6: for Wagon

    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      E24-2 (BO1) - E1-4 (+B1)*1 Always Below 1 Ω
      E24-2 (BO1) - E109-4 (+B1)*2 Always Below 1 Ω
      E24-12 (IGO1) - A97-28 (IG1) Always Below 1 Ω
      E24-12 (IGO1) - E30-1 (IG) Always Below 1 Ω
      E24-12 (IGO1) - 3C-51 (IG) Always Below 1 Ω
      E24-12 (IGO1) - E19-4 (IG) Always Below 1 Ω
      E24-12 (IGO1) - O3-4 (IG) Always Below 1 Ω
      E24-12 (IGO1) - E98-18 (IG)*3 Always Below 1 Ω
      E24-12 (IGO1) - L70-1 (IG)*4 Always Below 1 Ω
      E24-12 (IGO1) - L88-1 (IG)*5 Always Below 1 Ω
      E24-12 (IGO1) - Q15-1 (IG)*6 Always Below 1 Ω
      E24-2 (BO1) - Body ground Always 10 kΩ or higher
      E24-12 (IGO1) - Body ground Always 10 kΩ or higher

      • *1: for Radio and Display Receiver Assembly Type

      • *2: for Radio Receiver Assembly Type

      • *3: w/ TOYOTA Parking Assist-Sensor System

      • *4: for Sedan

      • *5: for Hatchback

      • *6: for Wagon

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR