ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1241, C1242

DTC Code DTC Name
C1241 Low or High Power Supply Voltage
C1242 Open Circuit in IG1/IG2 Power Source Circuit

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU assembly power source voltage drops, or there is insufficient voltage to operate either ABS main relay 1 or ABS main relay 2, the skid control ECU assembly will store these codes.

These codes may be also be stored if the auxiliary battery voltage drops below 9.5 V.

Tech Tips

DTC C1256 (Accumulator Low Pressure) may also be memorized if there is a drop in power source voltage.

DTC Code INF Code DTC Detection Condition Trouble Area
C1241 81

System main relay 1 is under the following conditions when the power switch is on (READY):


  1. With the main relay 1 and the relay contact on, the voltage of relay power supply terminal (BS01) is less than 8.9 V and the actual current, which is supplied by the relay, does not reach the specified value at any of the linear solenoids for 0.03 seconds or more.

  2. With the main relay 1 and the relay contact on, the voltage of relay power supply terminal (BS01) is less than 8.9 V and the brake pedal is not depressed for 3 seconds or more.

  3. When 0.05 seconds elapsed after main relay 1 is turned on and the relay contact is on, the voltage of relay power supply terminal (BS01) is less than 8.9 V and even one wheel is prohibited from braking while depressing the brake pedal.

  4. While the main relay 1 on continues, skid control ECU assembly activation power source input terminal (+BI1 or +BI3) becomes less than 8.5 V and the relay contact off continues for 0.2 seconds or more.

  5. With the pressure sensor power supply voltage (VCM) 4.7 V or less or 5.3 V or more, skid control ECU assembly activation power source input terminal (+BI1 or +BI3) in the relevant lines is 8.5 V or less for 0.05 seconds or more.

  6. The sensor power source voltage (VCSK) is 4.7 V or less or 5.4 V or more for 0.2 seconds.

  • Auxiliary battery

  • Hybrid control system (Charging circuit)
↑ 82

System main relay 2 is under the following conditions when the power switch is on (READY):


  1. With the main relay 2 and the relay contact on, the voltage of relay power supply terminal (BS02) is less than 8.9 V and the actual current, which is supplied by the relay, does not reach the specified value at any of the linear solenoids for 0.03 seconds or more.

  2. With the main relay 2 and the relay contact on, the voltage of relay power supply terminal (BS02) is less than 8.9 V and the brake pedal is not depressed for 3 seconds or more.

  3. When 0.05 seconds elapsed after main relay 2 is turned on and the relay contact is on, the voltage of relay power supply terminal (BS02) is less than 8.9 V and even one wheel is prohibited from braking while depressing the brake pedal.

  4. While the main relay 2 on continues, skid control ECU assembly activation power source input terminal (+BI2 or +BI4) becomes less than 8.5 V and the relay contact off continues for 0.2 seconds or more.

  5. With the pressure sensor power supply voltage (VCM2) 4.7 V or less or 5.3 V or more, skid control ECU assembly activation power source input terminal (+BI2 or +BI4) in the relevant lines is 8.5 V or less for 0.05 seconds or more.

  6. The sensor power source voltage (VCSK) is 4.7 V or less or 5.4 V or more for 0.2 seconds.

 ↑
↑ 83 With the power switch on (READY), the capacitor mode signal is received from the brake control power supply assembly while the vehicle is driven at low speed for 7 seconds or more, or the vehicle is driven at medium to high speed for 3 seconds or more.

  • Auxiliary battery

  • Brake control power supply assembly
↑

91

92

Either of the following is detected:


  1. The voltage of terminal IG1 or IG2 is 3.5 V or more, and when the vehicle speed is 3 km/h (1.9 mph) or more, the voltage of terminal IG1 is 9.5 V or less for 10 seconds.

  2. The voltage of terminal IG1 or IG2 is 3.5 V or more, and when the vehicle speed is 3 km/h (1.9 mph) or more, the voltage of terminal (+BI1 or +BI3) or (+BI2 or +BI4) is 8.5 V or less for 10 seconds.

  • Auxiliary battery

  • Hybrid control system (Charging circuit)
↑

93

94

Either of the following is detected:


  1. The voltage of terminal IG1 is 3.5 V or more, and with the voltage of terminal +BI1 or +BI3 at 8.5 V or less, the front wheel speed sensor RH and rear wheel speed sensor LH power supply voltage decreases for 60 seconds or more.

  2. The voltage of terminal IG2 is 3.5 V or more, and with the voltage of terminal +BI2 or +BI4 at 8.5 V or less, the front wheel speed sensor LH and rear wheel speed sensor RH power supply voltage decreases for 60 seconds or more.

 ↑
C1242 87 The power supply voltage is not applied to the IG1 terminal, power supply voltage is applied to the IG2 terminal, and +BI1 terminal voltage is 9.5 V or more for 4 seconds or more.

  • Auxiliary battery

  • IG1 power source circuit

  • Hybrid control system (Charging circuit)

  • Skid control ECU assembly
↑ 88 With the vehicle wheel speed at 10 km/h or more and the communication with the power management control ECU functioning normally, power supply voltage is applied to the IG1 terminal, power supply voltage is not applied to the IG2 terminal, and +BI1 terminal voltage is 9.5 V or more for 4 seconds or more.

  • Auxiliary battery

  • IG2 power source circuit

  • Hybrid control system (Charging circuit)

  • Skid control ECU assembly

WIRING DIAGRAM

B002BTNE07
B002B9ZE08

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU assembly, perform initialization and calibration of the linear solenoid valve Click here.

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

PROCEDURE


  1. CHECK HYBRID CONTROL SYSTEM


    1. Check if the hybrid control system DTC is output (for 2GR-FXE: See page , for 2AR-FSE: Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output (for 2GR-FXE) B
      DTC is output (for 2AR-FSE) C

    B

    INSPECT HYBRID CONTROL SYSTEM Click here

    C

    INSPECT HYBRID CONTROL SYSTEM Click here

    A

  2. CHECK DTC


    1. Check that no main relay, stroke sensor and/or brake control power supply assembly DTCs are output Click here.

      Result
      Result Proceed to
      Main relay, stroke sensor and brake control power supply assembly DTC is not output A
      Main relay, stroke sensor and/or brake control power supply assembly DTC is output B

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  3. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      Auxiliary battery Power switch on (IG) 11 to 14 V
      Auxiliary battery Power switch on (READY) 11 to 15.5 V

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  4. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


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

      B002B4EE01

    2. Disconnect the skid control ECU assembly connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A14-43 (+BI1) - Body ground Always 11 to 14 V
      A16-38 (+BI2) - Body ground Always 11 to 14 V
      A14-29 (+BI3) - Body ground Always 11 to 14 V
      A16-22 (+BI4) - Body ground Always 11 to 14 V
      A14-46 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      A16-46 (IG2) - Body ground Power switch on (IG) 11 to 14 V
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. Turn the power switch off.

      B002B4EE02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-1 (GND) - Body ground Always Below 1 Ω
      A16-1 (GND4) - Body ground Always Below 1 Ω
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  6. RECONFIRM DTC


    1. Reconnect the skid control ECU assembly connectors.

    2. Clear the DTCs Click here.

    3. Turn the power switch on (IG).

    4. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTCs (C1241 and C1242) are not output A
      DTCs (C1241 and/or C1242) are 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 Click here.


    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE SKID CONTROL ECU ASSEMBLY Click here