ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1241/41, C1242/42

DTC Code DTC Name
C1241/41 Low Battery Positive Voltage
C1242/42 Open in IG1 / IG2 Power Source Circuit

DESCRIPTION

These codes are memorized when the power source voltage for the skid control ECU drops or the voltage for the ABS MAIN1 relay and ABS MAIN2 relay operation drops. The ABS MAIN1 relay and ABS MAIN2 relay are in the skid control ECU.

Tech Tips

DTC C1256/57 (accumulator low pressure) may be memorized if the power source voltage drops.

DTC Code Information Code DTC Detection Condition Trouble Area
C1241/41 81

Any of the following is detected in the ABS MAIN1 relay line, when the vehicle is in the ON state:


  1. With the ABS MAIN1 relay and the relay contact ON, the voltage of relay power supply terminal (BSO1) is below 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 ABS MAIN1 relay and the relay contact ON, the voltage of relay power supply terminal (BSO1) is below 8.9 V and the brake pedal is not depressed for 3 seconds or more.

  3. When 0.05 seconds elapsed after ABS MAIN1 relay is turned on and the relay contact is ON, the voltage of relay power supply terminal (BSO1) is below 8.9 V and even one wheel is prohibited from braking while depressing the brake pedal.

  4. While the ABS MAIN1 relay ON continues, skid control ECU activation power source input terminal (+BI1 or +BI3) becomes lower than 9.1 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 activation power source input terminal (+BI1 or +BI3) in the relevant lines is 9.1 V or less for 0.05 seconds or more.

  • Battery

  • ABS MAIN1 relay (Skid control ECU interior circuit)

  • ABS MAIN2 relay (Skid control ECU interior circuit)

  • Hybrid control system

  • Power source circuit
↑ 82

Any of the following is detected in the ABS MAIN2 relay line, when the vehicle is in the ON state:


  1. With the ABS MAIN2 relay and the relay contact ON, the voltage of relay power supply terminal (BSO2) is below 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 ABS MAIN2 relay and the relay contact ON, the voltage of relay power supply terminal (BSO2) is below 8.9 V and the brake pedal is not depressed for 3 seconds or more.

  3. When 0.05 seconds elapsed after ABS MAIN2 relay is turned on and the relay contact is ON, the voltage of relay power supply terminal (BSO2) is below 8.9 V and even one wheel is prohibited from braking while depressing the brake pedal.

  4. While the ABS MAIN2 relay ON continues, skid control ECU activation power source input terminal (+BI2 or +BI4) becomes lower than 9.1 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 activation power source input terminal (+BI2 or +BI4) in the relevant lines is 9.1 V or less for 0.05 seconds or more.

 ↑
↑ 83 With the power switch ON (READY), the capacitor mode signal is received from the brake control power supply 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.

  • Battery

  • Hybrid control system

  • Brake control power supply
↑

91

92

When any 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 9.1 V or less for 10 seconds

  • Battery

  • Hybrid control system

  • Power source circuit
↑

93

94

When any of the following is detected:


  1. The voltage of terminal IG1 is 3.5 V or more, and with the voltage of terminal +BI1 activation power source input terminal BI3 at 9.1 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 9.1 V or less, the front wheel speed sensor LH and rear wheel speed sensor RH power supply voltage decreases for 60 seconds or more

 ↑
C1242/42 87 The power supply voltage is not applied to the IG1 terminal (below 3.5 V), power supply voltage is applied to the IG2 terminal (3.5 V or more), and DI1 terminal voltage is 9.5 V or more for 4 seconds or more.

  • Power source circuit

  • Skid control ECU
↑ 88 The power supply voltage is applied to the IG1 terminal (3.5 V or more), power supply voltage is not applied to the IG2 terminal (below 3.5 V), and DI1 terminal voltage is 9.5 V or more for 4 seconds or more. ↑

WIRING DIAGRAM

A01GYILE13

INSPECTION PROCEDURE

Note

When replacing the skid control ECU, perform the following operations:


  • Initialization of linear solenoid valve and calibration Click here

  • Yaw rate and acceleration sensor zero point calibration Click here

PROCEDURE


  1. INSPECT BATTERY


    1. Check the battery voltage.

      Standard voltage
      11 to 14 V

    NG

    RECHARGE OR REPLACE BATTERY Click here

    OK

  2. CHECK DTC


    1. Clear the DTCs Click here.

    2. Turn the power switch OFF.

    3. Turn the power switch ON (IG).

    4. Check that the DTCs (electronically controlled brake system and hybrid control system) are recorded Click here.

      Result
      Result Proceed to
      DTCs (C1311/11, C1312/12, C1313/13, C1314/14 and hybrid control system malfunction) are not output A
      Hybrid control system DTC is output B
      DTCs (C1311/11, C1312/12, C1313/13 and C1314/14) are output C

    B

    GO TO HYBRID CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    C

    REPAIR CIRCUIT INDICATED BY OUTPUT CODE Click here

    A

  3. CHECK HARNESS AND CONNECTOR (IG1, IG2, +BI1, +BI2, +BI3, +BI4)


    1. A01H1MKE16

      Disconnect the A19 and A21 ECU connectors.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      A19-46 (IG1) - Body ground Power switch ON (IG) 11 to 14 V
      Power switch OFF Below 1 V
      A21-46 (IG2) - Body ground Power switch ON (IG) 11 to 14 V
      Power switch OFF Below 1 V
      A19-43 (+BI1) - Body ground Always 11 to 14 V
      A21-38 (+BI2) - Body ground Always 11 to 14 V
      A19-29 (+BI3) - Body ground Always 11 to 14 V
      A21-22 (+BI4) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (GND CIRCUIT)


    1. Disconnect the A19 and A21 ECU connectors.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A19-1 (GND) - Body ground Always Below 1 Ω
      A21-1 (GND4) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. RECONFIRM DTC


    1. Clear the DTC Click here.

    2. Turn the power switch ON (READY).

    3. After 2 minutes or more have elapsed, drive the vehicle 5 km/h (3 mph) or more for 20 seconds.

    4. Check if the same DTCs are recorded Click here.

      Result
      Result Proceed to
      DTCs (C1241/41 and C1242/42) are not output A
      DTCs (C1241/41 and C1242/42) are output for LHD B
      for RHD C

      Tech Tips

      If troubleshooting has been carried out according to the "PROBLEM SYMPTOMS TABLE", refer back to the table and proceed to the next step Click here.


    B

    REPLACE SKID CONTROL ECU Click here

    C

    REPLACE SKID CONTROL ECU Click here

    A

    USE SIMULATION METHOD TO CHECK Click here