Dtc C1246/46 Master Cylinder Pressure Sensor Malfunction


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT OPERATION

READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER SENSOR)

READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW)

RECONFIRM DTC

INSPECT SKID CONTROL ECU (STP TERMINAL)

DTC C1246/46 Master Cylinder Pressure Sensor Malfunction

DTC C1281/81 Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC)


DESCRIPTION

The master cylinder pressure sensor is connected to the skid control ECU in the brake actuator assembly.
DTC C1281/81 is deleted when the master cylinder pressure sensor sends a master cylinder pressure signal or Test Mode ends. DTC C1281/81 is output only in Test Mode.

Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.Brake Control.Vehicle Stability Control System. Dtc C1246/46 Master Cylinder Pressure Sensor Malfunction


DTC Code
DTC Detection Condition
Trouble Area
C1246/46
When one of the following conditions is met:
  1. At a vehicle speed of 7 km/h (4.3 mph) or more, the PMC terminal voltage is over 0.86 V and does not change by 0.005 V or more for 30 seconds.
  2. Noise occurs in the PMC terminal 7 times or more within 5 seconds.
  3. With the stop light switch OFF, the PMC terminal voltage is more than 0.86 V or less than 0.3 V for 5 seconds or more.
  4. With the IG1 terminal voltage between 9.5 and 17.2 V, the VCM terminal voltage is not between 4.4 and 5.6 V for 1.2 seconds or more.
  5. With the VCM terminal voltage between 4.4 and 5.6 V, the PCM terminal voltage is not between 0.14 and 4.85 V for 1.2 seconds or more.
  1. Stop light switch circuit
  2. Master cylinder pressure sensor circuit
  3. Brake actuator assembly (Master cylinder pressure sensor)
C1281/81
Detected only during Test Mode.
  1. Stop light switch
  2. Master cylinder pressure sensor

WIRING DIAGRAM

Refer to DTC C1249/49 (Toyota Fortuner RM000000XIE04EX_02.html).

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration (Toyota Fortuner RM000000XHR02TX.html).
1.CHECK STOP LIGHT OPERATION

  1. Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

    OK:

    Condition
    		Illumination Condition
    Brake pedal depressed
    		ON
    Brake pedal released
    		OFF


NG
INSPECT STOP LIGHT CIRCUIT
OK


2.READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine.

  1. Select the Data List mode on the intelligent tester (Toyota Fortuner RM000000XHW03RX.html).

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Master Cylinder Sensor
    		Master cylinder pressure sensor reading / min.: 0 V, max.: 5 V
    		When brake pedal is released: 0.3 to 0.9 V
    		Reading increases when brake pedal is depressed

  1. Check that the value of the master cylinder pressure sensor observed on the intelligent tester changes when the brake pedal is depressed.

    OK:
    When the pedal is depressed, the voltage displayed on the intelligent tester increases.


NG
REPLACE BRAKE ACTUATOR ASSEMBLY
OK


3.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW)

  1. Select the Data List mode on the intelligent tester (Toyota Fortuner RM000000XHW03RX.html).

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light SW
    		Stop light switch / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-

  1. Check that the stop light switch condition observed on the intelligent tester changes when the brake pedal is depressed.

    OK:
    When the brake pedal is depressed, the intelligent tester displays "ON".


NG
Go to step 5
OK


4.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Clear the DTC(s) (Toyota Fortuner RM000000XHV03YX.html).

  1. Start the engine.

  1. Drive the vehicle at a vehicle speed of 30 km/h (19 mph) and depress the brake pedal strongly for approximately 3 seconds to perform a braking test (decelerate the vehicle by depressing the brake pedal).

  1. Check if the same DTC is recorded (Toyota Fortuner RM000000XHV03YX.html).

    Result
    Result
    		Proceed to
    DTC not output
    		A
    DTC output
    		B


B
REPLACE BRAKE ACTUATOR ASSEMBLY
A

CHECK FOR INTERMITTENT PROBLEMS

5.INSPECT SKID CONTROL ECU (STP TERMINAL)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.Brake Control.Vehicle Stability Control System. Dtc C1246/46 Master Cylinder Pressure Sensor Malfunction

  1. Turn the ignition switch off.

  1. Disconnect the skid control ECU connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    S25-2 (STP) - Body ground
    		Stop light switch ON
    (Brake pedal depressed)
    		8 to 14 V
    S25-2 (STP) - Body ground
    		Stop light switch OFF
    (Brake pedal released)
    		Below 1.5 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
OK

REPLACE BRAKE ACTUATOR ASSEMBLY