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 (brake booster with master cylinder assembly) power source voltage drops, or there is insufficient voltage to operate the main relay, the skid control ECU (brake booster with master cylinder assembly) will store these DTCs.

If the auxiliary battery voltage is temporarily low, these DTCs may be stored.

Tech Tips

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

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1241 Low or High Power Supply Voltage

101

102

103

551

552

554

  • INF Code: 101


    • Either of the following is detected when the BS terminal voltage is 9.1 V or less:


      1. The brake is not applied for 3 seconds or more.

      2. The brake is applied for 0.05 seconds or more.

  • INF Code: 102


    • Any of the following is detected when the ECU internal voltage is 6.92 V or less:


      1. The relay output voltage is less than 3.5 V for 0.05 seconds or more, when the main relay operation command is on.

      2. The stroke sensor value invalid for 0.2 seconds or more.

      3. The reaction force pressure sensor value invalid for 0.2 seconds or more.

      4. The servo pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more.

      5. The servo pressure sensor value invalid for 0.2 seconds or more.

      6. The reaction force pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more.

  • INF Code: 103


    • When the ECU internal voltage is 8.3 V or less, the accumulator pressure sensor value is invalid for 0.8 seconds or more.

    • Either of the following is detected when the ECU internal voltage is 6.9 V or less:


      1. When the accumulator pressure sensor value is 15 MPa (153 kgf/cm2, 2176 psi) or less, the pump motor does not operate for 1 second or more.

      2. Both the motor relay 1 and 2 cannot be operated for 0.2 seconds or more.

  • INF Code: 551


    • Either of the following is detected when the BS voltage of the ABS unit is 9.1 V or less:


      1. The brake is not applied for 3 seconds or more.

      2. The brake is applied for 0.05 seconds or more.

  • INF Code: 552


    • The speed sensor power voltage is invalid for 60 seconds or more.

  • INF Code: 554


    • The voltage of IG1 or IG2 is 9.5 V or less for 10 seconds or more.

  • Improperly connected connector, deformation or corrosion of terminals

  • Auxiliary battery

  • Hybrid control system (Charging circuit)

  • Skid control ECU (brake booster with master cylinder assembly)

 Electronically controlled brake system DTC
C1242 Open Circuit in IG1/IG2 Power Source Circuit

111

112

  • INF Code: 111


    • When the IG1 terminal voltage is less than 3.5 V, the IG2 terminal voltage is 9.5 V or more for 4 seconds or more.

  • INF Code: 112


    • When communication with the hybrid vehicle control ECU is normal or the vehicle speed is 10 km/h (6 mph) or more, and the IG1 terminal voltage is 9.5 V or more, the IG2 terminal voltage is less than 3.5 V for 4 seconds or more.

  • INF Code: 111


    • Open or short in IG1 circuit

    • Improperly connected connector, deformation or corrosion of terminals

    • Smart entry and start system (IG start circuit)

    • Auxiliary battery

    • Hybrid control system (Charging circuit)

    • Skid control ECU (brake booster with master cylinder assembly)

  • INF Code: 112


    • Open or short in IG2 circuit

    • Improperly connected connector, deformation or corrosion of terminals

    • Smart entry and start system (IG start circuit)

    • Auxiliary battery

    • Hybrid control system (Charging circuit)

    • Skid control ECU (brake booster with master cylinder assembly)

 Electronically controlled brake system DTC
DTC Detection Conditions: C1241 INF Code: 101
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition When the BS terminal voltage is 9.1 V or less. ○ ○
Malfunction Status The brake is not applied. ○ -
The brake is applied. - ○
Detection Time 3 seconds or more 0.05 seconds or more
Number of Trips 1 trip 1 trip

Tech Tips

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

DTC Detection Conditions: C1241 INF Code: 102
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3 Pattern 4 Pattern 5 Pattern 6
Diagnosis Condition When the ECU internal voltage is 6.92 V or less. ○ ○ ○ ○ ○ ○
Malfunction Status The relay output voltage is less than 3.5 V, when the main relay operation command is on. ○ - - - - -
The value of the stroke sensor is invalid. - ○ - - - -
The value of the reaction force pressure sensor is invalid. - - ○ - - -
The servo pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more. - - - ○ - -
The value of the servo pressure sensor is invalid. - - - - ○ -
The reaction force pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more. - - - - - ○
Detection Time 0.05 seconds or more 0.2 seconds or more 0.2 seconds or more 0.06 seconds or more 0.2 seconds or more 0.06 seconds or more
Number of Trips 1 trip 1 trip 1 trip 1 trip 1 trip 1 trip

Tech Tips

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

DTC Detection Conditions: C1241 INF Code: 103
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3
Diagnosis Condition ECU internal voltage is 8.3 V or less. ○ - -
ECU internal voltage is 6.9 V or less. - ○ ○
Malfunction Status The value of the accumulator pressure sensor is invalid. ○ - -

When the accumulator pressure sensor value is 15 MPa (153 kgf/cm2, 2176 psi) or less, the pump motor does not operate.

 - ○ -
Both the motor relay 1 and 2 cannot be operated. - - ○
Detection Time 0.8 seconds or more 1 second or more 0.2 seconds or more
Number of Trips 1 trip 1 trip 1 trip

Tech Tips

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

DTC Detection Conditions: C1241 INF Code: 551
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition The BS voltage of the ABS unit is 9.1 V or less. ○ ○
Malfunction Status The brake is not applied. ○ -
The brake is applied. - ○
Detection Time 3 seconds or more 0.05 seconds or more
Number of Trips 1 trip 1 trip

Tech Tips

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

WIRING DIAGRAM

A001Q7AE06

CAUTION / NOTICE / HINT

Note


  • After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

    Click here

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

PROCEDURE


  1. CHECK SMART ENTRY AND START SYSTEM (for Start Function)


    1. Check if smart entry and start system (for start function) DTCs are output.

      Click here


      Body Electrical > Entry&Start > Trouble Codes
      Body Electrical > Power Source Control > Trouble Codes
      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

    B

    INSPECT SMART ENTRY AND START SYSTEM (for Start Function) Click here

    A

  2. CHECK DTC (HYBRID CONTROL SYSTEM)


    1. Check if hybrid control system DTCs are output.

      Click here


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

    B

    INSPECT HYBRID CONTROL SYSTEM Click here

    A

  3. CHECK DTC


    1. Check that no main relay malfunction DTCs are output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      Main relay malfunction DTCs are not output. A
      Main relay malfunction DTCs are output. B

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  4. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

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

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. A005NB5C80
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Turn the power switch off.

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

      OK
      The connector is securely connected.

    3. Disconnect the A39 skid control ECU (brake booster with master cylinder assembly) connector.

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

      OK
      No deformation or corrosion.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A39-15 (+BI1) - Body ground Always 11 to 14 V
      A39-5 (+BI2) - Body ground Always 11 to 14 V
      A39-52 (BS) - Body ground Always 11 to 14 V
      A39-23 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      A39-9 (IG2) - Body ground Power switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  6. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A001RR7C81
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Turn the power switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A39-26 (GND1) - Body ground Always Below 1 Ω
      A39-39 (GND2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  7. RECONFIRM DTC


    1. Reconnect the A39 skid control ECU (brake booster with master cylinder assembly) connector.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the power switch off.

    4. Turn the power switch on (IG).

    5. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTCs C1241 and C1242 are not output. A
      DTCs C1241 and/or C1242 are output. (for LHD) B
      DTCs C1241 and/or C1242 are output. (for RHD) C

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here