Toyota Venza: Master Cylinder Pressure Sensor Malfunction (C1246/46,C1281/81)

Toyota Venza Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System / Master Cylinder Pressure Sensor Malfunction (C1246/46,C1281/81)

DESCRIPTION

Master cylinder pressure sensor is connected to the skid control ECU in the brake actuator assembly.

DTC C1281/81 will be cleared when the master cylinder pressure sensor sends a master cylinder pressure signal or when Test Mode ends. DTC C1281/81 is output only in Test Mode.

DTC Code	DTC Detection Condition	Trouble Area
C1246/46	Any of the following is detected: The voltage of the sensor signal is out of range (below 0.129 V, above 3.29 V). The sensor supply voltage is out of range (above 5.3 V, below 4.5 V). The sensor signal offset value is out of range.	Stop light switch circuit Master cylinder pressure sensor circuit Brake actuator assembly (Master cylinder pressure sensor)
C1281/81	Detected only during Test Mode.	Stop light switch Brake pedal load sensing switch Master cylinder pressure sensor

WIRING DIAGRAM

Refer to DTC C1249/49 (See page ).

PROCEDURE

1.	CHECK STOP LIGHT OPERATION

(a) 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

INSPECT STOP LIGHT CIRCUIT

2.	READ VALUE USING TECHSTREAM (MASTER CYLINDER PRESSURE SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Master Cylinder Sensor	Master cylinder pressure sensor reading / Min.: 0 V, Max.: 5 V	Brake pedal released: 0.3 to 0.9 V	Reading increases when brake pedal is depressed

(d) Check that the brake fluid pressure value of the master cylinder pressure sensor observed on the Techstream changes when the brake pedal is depressed.

OK:

When the pedal is depressed, voltage displayed on the Techstream increases.

REPLACE BRAKE ACTUATOR ASSEMBLY

3.	READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

(a) Select the Data List on the Techstream (See page ).

ABS/VSC/TRAC

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	-

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

(b) Check that the stop light condition observed on the Techstream changes when the brake pedal is depressed.

OK:

When the brake pedal is depressed, the Techstream displays "ON".

GO TO STEP 5

4.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs (See page ).

(d) At a speed of 30 km/h (18 mph) or more, drive the vehicle and perform braking test (decelerate the vehicle by depressing the brake pedal).

(e) Check if the same DTC is recorded (See page ).

Result	Proceed to
DTC (C1246/46) is not output	A
DTC (C1246/46) is output	B

CHECK FOR INTERMITTENT PROBLEMS

REPLACE BRAKE ACTUATOR ASSEMBLY

5.	INSPECT SKID CONTROL ECU (STP TERMINAL)

(a) Turn the ignition switch off.

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A42-30 (STP) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
A42-30 (STP) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

Text in Illustration

*1	Front view of wire harness connector (to Brake Actuator (Skid Control ECU))

REPLACE BRAKE ACTUATOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

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