VEHICLE STABILITY CONTROL SYSTEM, 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 meets one of the DTC detection conditions 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
C1241 Low Power Supply Voltage Malfunction

Any of the following is detected:


  1. The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage (soft low voltage) is less than 9.6 V for 1 second or more.

  2. The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage (hard low voltage) is less than 6.9 V for 1 second or more.

  3. The vehicle speed is 15 km/h (9 mph) or more, the +BS terminal voltage is 9.6 V or more, the skid control ECU (brake actuator assembly) turns on more than one valve at the same time within a short period of time and the valve relay supply voltage drop exceeds the threshold.*

  4. The +BS terminal voltage is less than 6.7 V and the skid control ECU (brake actuator assembly) judges that power supply voltage is abnormal for 0.06 seconds or more.

  • ABS NO. 2 fuse

  • Battery

  • Charging system

  • Power source circuit

  • Ground circuit

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

*: The skid control ECU (brake actuator assembly) monitors the resistance of the power source line at the +BS terminal. A malfunction is detected when an abnormality occurs in the +BS terminal wire harness or its connection and the skid control ECU (brake actuator assembly) determines that the wiring resistance at the +BS terminal exceeds the standard resistance.

DTC Detection Conditions: C1241
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3 Pattern 4
Diagnosis Condition The vehicle speed is 6 km/h (4 mph) or more. ○ ○ - -
The vehicle speed is 15 km/h (9 mph) or more and the +BS terminal voltage is 9.6 V or more. - - ○ -
The +BS terminal voltage is less than 6.7 V. - - - ○
Malfunction Status The +BS terminal voltage (soft low voltage) is less than 9.6 V. ○ - - -
The +BS terminal voltage (hard low voltage) is less than 6.9 V. - ○ - -
The skid control ECU (brake actuator assembly) turns on more than one valve at the same time within a short period of time and the valve relay supply voltage drop exceeds the threshold.* - - ○ -
The skid control ECU (brake actuator assembly) judges that power supply voltage is abnormal. - - - ○
Detection Time 1 second or more 1 second or more - 0.06 seconds or more
Number of Trips 1 trip 1 trip 1 trip 1 trip

*: The skid control ECU (brake actuator assembly) monitors the resistance of the power source line at the +BS terminal. A malfunction is detected when an abnormality occurs in the +BS terminal wire harness or its connection and the skid control ECU (brake actuator assembly) determines that the wiring resistance at the +BS terminal exceeds the standard resistance.

Tech Tips

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

WIRING DIAGRAM

B006ZANE03

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration.

    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 Ignition switch off 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY for 2AR-FE: Click here
    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY for A25A-FKS: Click here
    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY for 2GR-FKS: Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. B0071RIC69
      *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.

      OK
      The connector is securely connected.

    2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK
      No deformation or corrosion.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A34-30 (+BS) - Body ground Always 11 to 14 V
      A34-36 (IG1) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B0071RIC70
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A34-46 (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 A34 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Perform a road test.

    6. Check if the same DTC is output.


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