VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C120B

DTC Code DTC Name
C120B IG Supply Voltage Low

DESCRIPTION

DTC No. Detection Item DTC Detection Condition Trouble Area
C120B IG Supply Voltage Low

Either of the following is detected:


  1. The voltage at terminal IG1 is currently 8.4 V or less or there is a record of the voltage being 8.4 V or less, and there is a master cylinder pressure sensor output malfunction for 0.2 seconds or more.

  2. Noise occurs in the PMC terminal 0.2 seconds or more.

  • Low power supply voltage

  • Skid control ECU (brake actuator assembly)

  • Backup boost converter circuit (w/ stop and start system)

WIRING DIAGRAM

Refer to DTC C1241.

Click here

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure (w/o Stop and Start System).

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)


    1. A01MV8BC24
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Make sure that there is no looseness at the locking part and the connecting part of the connector.

    2. Disconnect the A15 skid control ECU (brake actuator assembly) connector.

    3. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A15-34 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (w/o Stop and Start System) B
      NG (w/ Stop and Start System) C

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    C

    INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT) Click here

    A

  2. RECONFIRM DTC


    1. Reconnect the A15 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C120B is not output. A
      DTC C120B is output. B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY for RHD: Click here