ELECTRONICALLY CONTROLLED BRAKE SYSTEM(w/ Vacuum Brake Booster), Diagnostic DTC:C1241

DTC Code DTC Name
C1241 Low Power Supply Voltage Malfunction

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU (brake actuator assembly) stores this DTC and the fail-safe function prohibits ABS operation.

This DTC is stored when the +BS terminal voltage deviates due to a malfunction in the power supply or charging circuit such as the battery or alternator circuit, etc.

The DTC is cleared when the +BS terminal voltage returns to normal.

DTC No. Detection Item DTC Detection Condition Trouble Area Note
C1241 Low Power Supply Voltage Malfunction

Any of the following is detected:


  • At a vehicle speed of 3 km/h (2 mph) or more, the +BS terminal voltage is less than 9.5 V for 10 seconds or more.

  • When the ABS solenoid relay remains on and the +BS terminal voltage is less than 9.5 V, the relay contact is open for 0.22 seconds or more.

  • With the +BS terminal voltage 9.5 V or less, the vehicle speed sensor power supply decreases for 60 seconds or more.

  • When fail-safe motor relay is on and +BS terminal voltage is below 9.5 V, fail-safe motor relay overcurrent continues for 0.05 seconds or more.

  • VSC NO. 2 fuse

  • Battery

  • Charging system

  • Power source circuit

  • Internal power supply circuit of the skid control ECU (brake actuator assembly)

 -
C1241 DTC Detection Conditions
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3 Pattern 4
Diagnosis Condition - - - - -
Malfunction Status At a vehicle speed of 3 km/h (2 mph) or more, the +BS terminal voltage is less than 9.5 V ○ - - -
When the ABS solenoid relay remains on and the +BS terminal voltage is less than 9.5V, the relay contact is open - ○ - -
With the +BS terminal voltage 9.5 V or less, the vehicle speed sensor power supply decreases - - ○ -
When fail-safe motor relay is on and +BS terminal voltage is below 9.5 V, fail-safe motor relay overcurrent continues - - - ○
Detection Time 10 seconds or more. 0.22 seconds or more. 60 seconds or more. 0.05 seconds or more.
Number of Trips 1 trip 1 trip 1 trip 1 trip

Tech Tips

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

B006D7AE31
*1 from IG circuit
*2 VSC NO. 2
*3 Skid Control ECU (Brake Actuator Assembly)

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.

PROCEDURE


  1. CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      Tester Connection Condition Specified Condition
      Positive (+) terminal - Negative (-) terminal Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 8GR-FKS: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for V35A-FTS: Click here

    OK

  2. CHECK TERMINAL VOLTAGE (+BS TERMINAL)


    1. Turn the engine switch off.

    2. Make sure that there is no looseness in the locking part and connecting part of the connectors.

    3. Disconnect the A9 skid control ECU (brake actuator assembly) connector.

    4. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A9-38 (+BS) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-25 (GND1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  4. RECONFIRM DTC


    1. Reconnect the A9 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the engine switch off.

    4. Start the engine.

    5. Perform a road test.

    6. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1241 is not output. A
      DTC C1241 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