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):

  • 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

Blinking

DTC stored

CONFIRMATION DRIVING PATTERN

  1. Tip:

    • When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).

    • 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.

      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 the 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.

    7. Keep the engine stopped by stop and start control for 1 second or more.

    8. Depress the clutch pedal and start the engine.

      Tip:

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

    9. Check that DTCs are not output.

      Click here

      Powertrain > Stop and Start > Trouble Codes

  2. STOP AND START SYSTEM OPERATION CHECK

    Tip:

    When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).

    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. 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

    6. Depress the clutch pedal and start the engine.

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.

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

Tip:

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)

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    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. A285704C04

      *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)

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    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ENGINE STOP AND START ECU

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    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR