ANTI-LOCK BRAKE 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 canceled when the +BS terminal voltage returns to normal.

DTC No. DTC Detection Condition Trouble Area
C1241

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.

  5. During the initial check after the ignition switch is turned ON, the +BS terminal voltage is less than 5.0 V for 0.5 seconds or more.

  6. The +BS terminal voltage is less than 2.6 V for 1 second 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.

WIRING DIAGRAM

A0136PTE03

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      11 to 14 V

    NG

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. A0136PEE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A46-25 (+BS) - Body ground Always 11 to 14 V
      A46-25 (+BS) - A46-38 (GND1) Always 11 to 14 V
      A46-28 (IG1) - Body ground Ignition switch ON 11 to 14 V
      A46-28 (IG1) - A46-38 (GND1) Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for +BS circuit) B
      NG (for IG1 circuit) C

    B

    CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    A

  3. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A0136PEE03
      Text in Illustration
      *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
      A46-38 (GND1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  4. RECONFIRM DTC


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

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Perform a road test.

    6. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1241 is not output. A
      DTC C1241 is output. B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts Click here.


    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS

  5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)


    1. Turn the ignition switch off.

    2. Disconnect the 1B engine room relay block and junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A46-25 (+BS) - 1B-5 Always Below 1 Ω

      Tech Tips


      • Even if the resistance between the skid control ECU (brake actuator assembly) and the engine room relay block and junction block assembly is normal, there may be an abnormality in the resistance of the wiring between the battery and the engine room relay block and junction block assembly. Therefore, be sure to inspect the circuit between the battery and the engine room relay block and junction block assembly before replacing the skid control ECU (brake actuator assembly).

      • If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts Click here.


    NG

    REPAIR OR REPLACE WIRE HARNESS OR ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here