Toyota Sienna Service Manual: Master Cylinder Pressure Sensor Malfunction
DTC C1246/46 Master Cylinder Pressure Sensor Malfunction
DESCRIPTION
Master cylinder pressure sensor is connected to the skid control ECU in the actuator.
INSPECTION PROCEDURE
1 READ VALUE ON INTELLIGENT TESTER (MASTER CYLINDER PRESSURE SENSOR)
(a) Connect the intelligent tester to the DLC3.
(b) Start the engine.
(c) Select the DATA LIST mode on the intelligent tester.
ABS / VSC: 
(d) Check that the brake fluid pressure value of the master cylinder pressure sensor indicated on the intelligent tester, changes when the brake pedal is depressed.
OK: Brake fluid pressure value should change.
NOTICE: When replacing the brake actuator assembly, perform zero point calibration (See page BC-70).
REPLACE BRAKE ACTUATOR ASSEMBLY
2 INSPECT SKID CONTROL ECU (STP1 TERMINAL)
(a) Disconnect the skid control ECU connector.
(b) Measure the voltage according to the value(s) in the table below
Standard voltage
NOTICE: When replacing the brake actuator assembly, perform zero point calibration (See page BC-70).
REPLACE BRAKE ACTUATOR ASSEMBLY
Low Battery Positive Voltage
DTC C1241/41 Low Battery Positive Voltage
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT ECU-IG FUSE
(a) Remove the ECU-IG fuse from the driver side J/B.
(b) Check continu ...
Open in Stop Light Switch Circuit
DTC C1249/49 Open in Stop Light Switch Circuit
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
1 CHECK STOP LIGHT SWITCH OPERATION
(a) Check that the stop light comes on when the brak ...
Other materials:
Removal
1. REMOVE FRONT WHEEL
2. REMOVE REAR WHEEL
3. REMOVE TIRE PRESSURE WARNING VALVE AND TRANSMITTER
(a) Remove the valve core and cap, and release the air
from the tire.
(b) After ensuring that a sufficient amount of air has
been released, remove the nut and washer that are
used to secure ...
Removal
1. DISCONNECT CABLE FROM NEGATIVE BATTERY
TERMINAL
2. REMOVE HEATED OXYGEN SENSOR (for Bank 1
Sensor 2)
(a) Disconnect the sensor connector under the center
console.
(b) Using SST, remove the heated oxygen sensor.
SST 09224-00010
3. REMOVE FRONT EXHAUST PIPE ASSEMBLY
(a) Disconnect ...
When servicing full-time 4wd vehicles
The full-time 4WD SIENNA is equipped with the open
center differential system.
If incorrect preparations or test procedures are used, the
test will not only be unsuccessful, but may be dangerous
as well.
Therefore, before beginning any such servicing or test,
be sure to check the following ...