STOP AND START SYSTEM, Diagnostic DTC:B22C0

DTC Code DTC Name
B22C0 BBC Overcurrent

DESCRIPTION

A backup boost converter is built into the engine stop and start ECU.

The backup boost converter helps maintain battery voltage to prevent various functions from failing if power source voltage supplied to the audio and visual system, etc. drops due to the high electrical load when the engine is restarted by stop and start control.

The backup boost converter helps maintain the power source voltage if the battery voltage drops due to the high electrical load when the engine is restarted by stop and start control.

The backup boost converter helps maintain the power source voltage at 13.5 V when its mode changes from standby mode to compensation mode. If the backup boost converter cannot maintain the voltage at the specified level when the engine is restarted by stop and start control, the engine stop and start ECU stores a DTC and blinks the stop and start cancel indicator light. The stop and start cancel indicator light will remain blinking during the trip in which the malfunction occurred.

Tip:

A relay function and fuse function are provided in the backup boost converter for the electrical systems that supply power to the main body ECU (multiplex network body ECU), combination meter assembly and radio and display receiver assembly. If there is a malfunction in any of the electrical system circuits connected to the backup boost converter, the fuse function operates to protect the malfunctioning electrical system circuit and the relay function shuts off the circuit until the end of the trip. When the electrical system circuit is shut off, power to the circuit is cut off, causing any systems connected to the circuit to be disabled.

The fuse function is reset*1 when the ignition switch is turned off. If the malfunction still exists in the electrical system circuit that has been shut off by the relay function, it will be shut off again by the relay and fuse functions the next time the ignition switch is turned to ON. The backup boost converter supplies power to the main body ECU (multiplex network body ECU), anti-lock brake system, power steering system, meter/gauge system, EC inner rear view mirror, TOYOTA parking assist-sensor system and audio and visual system.

*1: A semiconductor fuse self resets according to electric signal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

B22C0

BBC Overcurrent

The following condition continues for 1 second or more (1 trip detection logic):

  • Overcurrent is detected at the BO1 and IGO1 terminals in the engine stop and start ECU

  • Engine stop and start ECU

  • Wire harness or connector

  • Spiral w/sensor cable sub-assembly

  • Skid control ECU (Brake actuator assembly)

  • Power steering ECU assembly

  • Main body ECU (Multiplex network body ECU)

  • Radio and display receiver assembly

  • Inner rear view mirror assembly

  • Clearance warning ECU assembly (w/ TOYOTA Parking Assist-Sensor System)

Blinking

DTC stored

CONFIRMATION DRIVING PATTERN

  1. CONFIRMATION AFTER TROUBLESHOOTING

    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.

    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

A295481E01
A295482E01
A295479E02

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.

    Click here

  • 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.

    Click here

  • After replacing the engine stop and start ECU or airbag sensor assembly, perform deceleration sensor zero point clear and calibration

    Click here

  • 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.

    Click here

  • If electrical load from additional devices installed on the vehicle (aftermarket audio system, etc.) is applied to the BO1 or IGO1 terminal in the engine stop and start ECU, the fuse function of the backup boost converter may operate.

    If the fuse function of the backup boost converter operates, any systems connected to the BO1 or IGO1 terminal in the engine stop and start ECU will not operate.

PROCEDURE

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

    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 - EACH ECU OR SENSOR)

    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 w/sensor cable 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. 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

      E24-2 (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

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ENGINE STOP AND START ECU

    1. Disconnect the engine stop and start ECU connector.

      A295480C01

      *a

      Component without harness connected

      (Engine Stop and Start ECU)

      -

      -

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E24-2 (BO1) - A8-8 (GND)

      Always

      10 kΩ or higher

      E24-12 (IGO1) - A8-8 (GND)

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE ENGINE STOP AND START ECU

    Click hereClick here

    OK

  4. CHECK VEHICLE CONDITION (BO1, IGO1 CIRCUIT)

    1. Check that additional devices installed to the vehicle (aftermarket audio system, etc.) are not connected to the BO1 or IGO1 terminal circuit in the engine stop and start ECU.

      Result

      Result

      Proceed to

      Load from an additional device installed to the vehicle (aftermarket audio system, etc.) is not applied.

      A

      Load from an additional device installed to the vehicle (aftermarket audio system, etc.) is applied.

      B
    A

    GO TO TROUBLE AREAS (TROUBLESHOOTING PROCEDURE FOR ECUS CONNECTED TO BO1 AND IGO1 TERMINALS)

    B

    END (REMOVE ELECTRICAL LOAD FROM ADDITIONAL DEVICE)