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 from the backup boost converter 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.

Tech Tips

A relay function and fuse function are provided in the backup boost converter.

If there is a malfunction in any of the electrical system circuits connected to the backup boost converter, the fuse and relay functions shut off the malfunctioning circuit to protect other circuits (remains shut off until next 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* when the engine 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 engine switch is turned on (IG).

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


    The backup boost converter supplies power to:

  • Tire pressure warning system

  • Lighting system

  • G-book system (w/ Telematics Transceiver)

  • Navigation system

  • Audio and visual system

  • Blind spot monitor system

  • Auto glare-resistant EC mirror

  • Dynamic radar cruise control system

  • Pre-crash safety system

  • CAN communication system

  • Lane departure alert system

  • Air conditioning system

  • Vehicle stability control system

  • Auto glare-resistant EC mirror

  • Meter / gauge system

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 B41, B42, B43 and IG41 terminals in the engine stop and start ECU

  • Engine stop and start ECU

  • Wire harness or connector

  • Tire pressure warning ECU and receiver*1

  • Front door inside handle illumination light assembly RH

  • Front door inside handle illumination light assembly LH

  • Radio receiver assembly*2,*3

  • Multi-display assembly*4

  • Remote touch (remote operation board)*2

  • LEXUS display audio controller (remote operation board)*3

  • Blind spot monitor sensor LH*5

  • Blind spot monitor sensor RH*5

  • Inner rear view mirror assembly*5

  • Millimeter wave radar sensor assembly*6

  • Driving support ECU assembly*6

  • Network gateway ECU*7

  • Lane departure warning camera*8

  • Air conditioning control assembly

 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.

Click here


  1. CONFIRMATION AFTER TROUBLESHOOTING

    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.


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG) 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. Depress the brake pedal and stop the vehicle.

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

    8. Release the brake pedal with the shift lever in D to 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.

      Click here


      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. Depress the brake pedal and stop the vehicle.

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

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

WIRING DIAGRAM

B003WOQE04
B003V2VE04
B003SY0E01
B003WDPE01
B003TQ4E02
B003VVCE02

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.

    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 yaw rate sensor, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    Click here

  • When the engine stop and start ECU is replaced, check the oil pump assembly with solenoid.

    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.

    Click here

  • If electrical load from additional devices installed to the vehicle (aftermarket audio system, etc.) is applied to the B41, B42, B43 or IG41 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 B41, B42, B43 or IG41 terminal in the engine stop and start ECU will not operate.

  • If DTCs P2796 and B22C0 are output simultaneously, troubleshoot for DTC P2796 first, as a malfunction which causes DTC P2796 to be stored may also cause DTC B22C0 to be stored.

    Click here

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BBC NO. 1, BBC NO. 2 FUSES)


    1. Disconnect the A93 engine stop and start ECU connector.

    2. Remove the BBC NO. 1 and BBC NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A93-1 (BIN2) - BBC NO. 2 fuse terminal 2 Always Below 1 Ω
      A93-3 (BIN1) - BBC NO. 1 fuse terminal 2 Always Below 1 Ω
      A93-1 (BIN2) - Body ground Always 10 kΩ or higher
      BBC NO. 2 fuse terminal 2 - Body ground Always 10 kΩ or higher
      A93-3 (BIN1) - Body ground Always 10 kΩ or higher
      BBC NO. 1 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 K139 engine stop and start ECU connector.

    2. Disconnect the Q38 tire pressure warning ECU and receiver connector.*1

    3. Disconnect the N6 front door inside handle illumination light assembly RH connector.

    4. Disconnect the N21 front door inside handle illumination light assembly LH connector.

    5. Disconnect the K70 radio receiver assembly connector.*2

    6. Disconnect the K58 radio receiver assembly connector.*3

    7. Disconnect the K61 multi-display assembly connector.*4

    8. Disconnect the K78 remote touch connector.*3

    9. Disconnect the Q50 blind spot monitor sensor LH connector.*5

    10. Disconnect the Q51 blind spot monitor sensor RH connector.*5

    11. Disconnect the S6 inner rear view mirror assembly connector.*6

    12. Disconnect the B8 millimeter wave radar sensor assembly connector.*7

    13. Disconnect the M1 driving support ECU assembly connector.*7

    14. Disconnect the K47 Network gateway ECU connector.*8

    15. Disconnect the S9 lane departure warning camera connector.*9

    16. Disconnect the K65 air conditioning control assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K139-2 (B41) - Q38-7 (+B)*1 Always Below 1 Ω
      K139-2 (B41) - N6-1 (+) Always Below 1 Ω
      K139-2 (B41) - N21-1 (+) Always Below 1 Ω
      K139-12 (B42) - K70-17 (+B1)*2 Always Below 1 Ω
      K139-12 (B42) - K58-4 (+B1)*3 Always Below 1 Ω
      K139-11 (B43) - K61-12 (B)*4 Always Below 1 Ω
      K139-11 (B43) - K78-1 (+B)*3 Always Below 1 Ω
      K139-3 (IG41) - Q38-1 (IG)*1 Always Below 1 Ω
      K139-3 (IG41) - Q50-5 (BLB)*5 Always Below 1 Ω
      K139-3 (IG41) - Q51-5 (BRB)*5 Always Below 1 Ω
      K139-3 (IG41) - S6-1 (IG)*6 Always Below 1 Ω
      K139-3 (IG41) - B8-5 (IGB)*7 Always Below 1 Ω
      K139-3 (IG41) - M1-30 (B)*7 Always Below 1 Ω
      K139-3 (IG41) - K47-10 (IG1)*8 Always Below 1 Ω
      K139-3 (IG41) - S9-7 (IGB)*9 Always Below 1 Ω
      K139-3 (IG41) - K65-8 (IG+) Always Below 1 Ω
      K139-2 (B41) - Body ground Always 10 kΩ or higher
      K139-12 (B42) - Body ground Always 10 kΩ or higher
      K139-11 (B43) - Body ground Always 10 kΩ or higher
      K139-3 (IG41) - Body ground Always 10 kΩ or higher

      • *1: w/ Tire Pressure Warning System

      • *2: for Audio and Visual System (w/o Parallel Parking Assist Function)

      • *3: w/ Navigation System or Audio and Visual System (w/ Parallel Parking Assist Function)

      • *4: w/ Multi-display

      • *5: w/ Blind Spot Monitor System

      • *6: w/ Auto Glare-resistant EC Mirror

      • *7: w/ Pre-crash Safety System

      • *8: w/ Network Gateway ECU

      • *9: w/ Lane Departure Alert System

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ENGINE STOP AND START ECU


    1. Disconnect the A94, A94 and K139 engine stop and start ECU connectors.

      B003X3EC13
      *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
      K139-3 (IG41) - A94-6 (DGND) Always 10 kΩ or higher
      K139-2 (B41) - A94-6 (DGND) Always 10 kΩ or higher
      K139-11 (B43) - A94-6 (DGND) Always 10 kΩ or higher
      K139-12 (B42) - A94-6 (DGND) Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ENGINE STOP AND START ECU Click here

    OK

  4. CHECK VEHICLE CONDITION (B41, B42, B43, IG41 CIRCUIT)


    1. Check that additional devices installed to the vehicle (aftermarket audio system, etc.) are not connected to the B41, B42, B43 or IG41 terminal circuit of 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

    TROUBLESHOOT ECUS CONNECTED TO TERMINALS B41, B42, B43 AND IG41

    B

    END (REMOVE ADDITIONAL DEVICE)