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

If a malfunction is detected in the power supply circuit, the skid control ECU 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 will store these codes.

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

Tech Tips

DTC C1256/57 (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
C1241/41 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 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.

  • 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 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.

  • Auxiliary battery

  • Brake control power supply
↑

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 9.1 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 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, 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
↑ 88 The 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

WIRING DIAGRAM

A01NFZ6E02
A01NGYWE02

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK HYBRID CONTROL SYSTEM


    1. Check if the hybrid control system DTC is output Click here.

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

    B

    INSPECT HYBRID CONTROL SYSTEM Click here

    A

  2. CHECK DTC


    1. Check that no main relay and/or capacitor DTCs are output Click here.

      Result
      Result Proceed to
      Main relay and capacitor DTC is not output A
      Main relay and/or capacitor 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
      11 to 14 V

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  4. INSPECT SKID CONTROL ECU (POWER SOURCE TERMINAL)


    1. A01NECUE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

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

    2. Disconnect the skid control ECU connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A90-4 (+BI1) - Body ground Always 11 to 14 V
      A92-5 (+BI2) - Body ground Always 11 to 14 V
      A90-5 (+BI3) - Body ground Always 11 to 14 V
      A92-6 (+BI4) - Body ground Always 11 to 14 V
      A90-2 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      A91-5 (IG2) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  5. INSPECT SKID CONTROL ECU (GND TERMINAL)


    1. Turn the power switch off.

      A01NG2WE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      		 - -

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the skid control ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A89-1 (GND) - Body ground Always Below 1 Ω
      A90-3 (GND2) - Body ground Always Below 1 Ω
      A90-1 (GND3) - Body ground Always Below 1 Ω
      A91-3 (GND4) - Body ground Always Below 1 Ω
      A91-1 (GND5) - Body ground Always Below 1 Ω
      A92-3 (GND6) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  6. RECONFIRM DTC


    1. Reconnect the skid control ECU 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 (C1241/41 and C1242/42) are not output A
      DTCs (C1241/41 and/or C1242/42) 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.


    B

    REPLACE SKID CONTROL ECU Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here