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 is met for 1 second or more (1 trip detection logic):


  • Backup boost converter 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

  • B42 voltage is 6.0 V or less, backup boost converter is not overheating and backup boost converter output overcurrent is not detected

  • IG41 voltage is 6.0 V or less and backup boost converter output overcurrent is not detected

  • Engine stop and start ECU

  • Wire harness or connector

  • Battery

  • BBC NO. 1 fuse

  • BBC NO. 3 fuse

 Blinks DTC stored

CONFIRMATION DRIVING PATTERN

Tech Tips

DTCs for the stop and start system are not cleared 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 battery terminal, stop and start control is prohibited until refresh charge is completed.

      In this case, let the vehicle idle with the battery temperature at 11°C (51°F) or higher for 5 to 60 minutes to complete the refresh charge. (The refresh charge is complete when the Data List item Status of Battery Charge Control changes from "Refresh Charge Mode".)

    • If the GTS is not available and the Data List item Status of Battery Charge Control cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.

      If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.

    • After the refresh charge completes, turn the engine switch off, wait for at least 30 seconds, and then start the engine again.

      If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.

    • Allow the engine to idle for 3 minutes after the engine warms up and check that the engine 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.

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      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. for Automatic Transmission:

      Depress the brake pedal and stop the vehicle.

      for Manual Transmission:

      Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    7. Keep the engine stopped by stop and start control for 1 second or more. (for Automatic Transmission: Keep the shift lever in D.)

    8. for Automatic Transmission:

      Release the brake pedal with the shift lever in D to start the engine.

      for Manual Transmission:

      Depress the clutch pedal and start the engine.

      Tech Tips

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

    9. Check that DTCs are not output.

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      Powertrain > Stop and Start > Trouble Codes

  2. Tech Tips


    • If the cable is disconnected from the battery terminal, stop and start control is prohibited until refresh charge is completed.

      In this case, let the vehicle idle with the battery temperature at 11°C (51°F) or higher for 5 to 60 minutes to complete the refresh charge. (The refresh charge is complete when the Data List item Status of Battery Charge Control changes from "Refresh Charge Mode".)

    • If the GTS is not available and the Data List item Status of Battery Charge Control cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.

      If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.

    • After the refresh charge completes, turn the engine switch off, wait for at least 30 seconds, and then start the engine again.

      If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.

    STOP AND START SYSTEM OPERATION CHECK


    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 the confirmation driving pattern, obey all speed limits and traffic laws.

    4. for Automatic Transmission:

      Depress the brake pedal and stop the vehicle.

      for Manual Transmission:

      Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    5. Allow the engine to stop by stop and start control. (for Automatic Transmission: Keep the shift lever in D.)

    6. for Automatic Transmission:

      Release the brake pedal with the shift lever in D to start the engine.

      for Manual Transmission:

      Depress the clutch pedal and start the engine.

WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note


  • Before replacing the engine stop and start ECU, read the number of starter operations and total number of engine starts 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.

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  • for Automatic Transmission:

    When the engine stop and start ECU is replaced, check the electromagnetic oil pump.

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  • 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)


    1. Disconnect the G125 engine stop and start ECU connector.

    2. Remove the BBC NO. 1 and BBC NO. 3 fuses from the engine room relay block and junction block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G125-1 (BIN2) - BBC NO. 1 fuse terminal 2 Always Below 1 Ω
      G125-3 (BIN1) - BBC NO. 3 fuse terminal 2 Always Below 1 Ω
      G125-1 (BIN2) - Body ground Always 10 kΩ or higher
      G125-3 (BIN1) - Body ground Always 10 kΩ or higher
      BBC NO. 1 fuse terminal 2 - Body ground Always 10 kΩ or higher
      BBC NO. 3 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. A01SH05C06
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

      Disconnect the G125 and G127 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
      G125-1 (BIN2) - Body ground Always 9.5 to 14 V
      G125-3 (BIN1) - 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 Switch Condition Specified Condition
      G127-21 (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 G126 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
      G126-6 (DGND) - 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)


    1. Disconnect the G127 engine stop and start ECU connector.

    2. Disconnect the G40 radio and display receiver assembly connector.

    3. Disconnect the G32 air conditioning control assembly connector.

    4. Disconnect the A64 millimeter wave radar sensor assembly connector.

    5. Disconnect the Q4 forward recognition camera connector.

    6. Disconnect the 2D instrument panel junction block assembly (body ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G127-12 (B42) - G40-4 (+B1) Always Below 1 Ω
      G127-3 (IG41) - G32-2 (IG+) Always Below 1 Ω
      G127-3 (IG41) - A64-8 (IGB) Always Below 1 Ω
      G127-3 (IG41) - Q4-7 (IGB) Always Below 1 Ω
      G127-3 (IG41) - 2D-5 Always Below 1 Ω
      G127-12 (B42) - Body ground Always 10 kΩ or higher
      G127-3 (IG41) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR