Click here

VEHICLE STABILITY CONTROL SYSTEM (for Hydraulic Brake Booster), Diagnostic DTC:C1242

Click here
Click here Click here
DTC Code DTC Name
C1242 Open Circuit in IG1/IG2 Power Source Circuit
Click here

DESCRIPTION

If there is a problem with the master cylinder solenoid (skid control ECU) power supply circuit, the skid control ECU stores DTCs and prohibits operation under the fail-safe function.

If the voltage supplied to the IG2 terminal is within the DTC detection range due to malfunctions in components such as the battery and generator circuit, this DTC is stored.

DTC Code DTC Detection Condition Trouble Area
C1242 The vehicle speed is 3 km/h (2 mph) or more and the voltage at the ECU IG2 terminal remains below 6.5 V for more than 7 seconds.

  • Battery

  • IGN fuse

  • Charging system

  • Harness or connector

  • Master cylinder solenoid (Skid control ECU)
Click here

WIRING DIAGRAM

Click here

INSPECTION PROCEDURE

Note:

  • When replacing the master cylinder solenoid, perform calibration (Click here).

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

Click here

PROCEDURE


  1. Click here

    CHECK TERMINAL VOLTAGE (IG2)


    1. Disconnect the A8 skid control ECU connector.

    2. A01DU42E03

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A8-1 (IG2) - Body ground Ignition switch ON 11 to 14 V
      Table 1. Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

  2. Click here

    CHECK HARNESS AND CONNECTOR (GND1, GND2 AND GND3 TERMINAL)


    1. Disconnect the A7 and A8 skid control ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A7-1 (GND1) - Body ground Always Below 1 Ω
      A7-32 (GND2) - Body ground Always Below 1 Ω
      A8-4 (GND3) - Body ground Always Below 1 Ω

  3. Click here

    RECONFIRM DTC


    1. Clear the DTCs (Click here).

    2. Check if the same DTC is output (Click here).

      Tip:

      Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

      Table 2. Result
      Result Proceed to
      DTC is not output A
      DTC is output (for LHD) B
      DTC is output (for RHD) C

  4. Click here

    REPLACE MASTER CYLINDER SOLENOIDClick here

  5. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. Click here

    USE SIMULATION METHOD TO CHECKClick here

  8. Click here

    REPLACE MASTER CYLINDER SOLENOIDClick here