C1281

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1246/46: Master Cylinder Pressure Sensor Malfunction

DTC C1246/46 - Master Cylinder Pressure Sensor Malfunction

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

DTC C1364/61 - Wheel Cylinder Pressure Sensor Malfunction

DESCRIPTION

The master cylinder pressure sensor and the wheel cylinder pressure sensor are built into the brake actuator. They measure the master cylinder pressure and wheel cylinder pressure and send the data to the skid control ECU.
DTC C1281/81 can be deleted when the master cylinder pressure sensor sends a master cylinder pressure signal or the Test Mode ends. DTC C1281/81 is output only in the Test Mode.














WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- When replacing the skid control ECU, perform the following operations:

- Initialization of linear solenoid valve and calibration Programming and Relearning
- Yaw rate and acceleration sensor zero point calibration Programming and Relearning
- When replacing the brake actuator, perform initialization of the linear solenoid valve and calibration Programming and Relearning.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR)





(a) Disconnect the A19 and A21 ECU connectors.
(b) Disconnect the A27 actuator connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. READ VALUE USING INTELLIGENT TESTER OR TECHSTREAM (MASTER CYLINDER PRESSURE SENSOR)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the power switch ON (IG).
(c) Select the DATA LIST mode on the intelligent tester or Techstream.
(1) Intelligent tester

ABS/VSC:





(2) Techstream

ABS/VSC/TRAC:





(d) Check the output value of the master cylinder pressure sensor on the intelligent tester or Techstream display.
OK:
When the pedal is depressed, the voltage displayed on the intelligent tester or Techstream increases.
NG -- REPLACE BRAKE ACTUATOR
OK -- Continue to next step.
3. READ VALUE USING INTELLIGENT TESTER OR TECHSTREAM (WHEEL CYLINDER PRESSURE SENSOR)
(a) Connect the pedal effort gauge.
(b) Install the LSPV gauge (SST) and bleed air Service and Repair.
SST: 09709-29018
(c) Connect the intelligent tester or Techstream to the DLC3.
(d) Select the DATA LIST mode on the intelligent tester or Techstream.
(1) Intelligent tester

ABS/VSC:





(2) Techstream

ABS/VSC/TRAC:





(e) Check the output value of the wheel cylinder pressure sensor at each fluid pressure during the electronically controlled brake system control.
Standard voltage:
Front wheel cylinder pressure sensor
Rear wheel cylinder pressure sensor










NG -- REPLACE BRAKE ACTUATOR
OK -- Continue to next step.
4. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Perform the road and braking test.
(c) Check if the same DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.
HINT: Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result





B -- USE SIMULATION METHOD TO CHECK
A -- Continue to next step.
5. CHECK FREEZE FRAME DATA
(a) Check the information code from the "FREEZE FRAME DATA" memorized when the DTCs (C1246/46 and C1364/61) are stored Freeze Frame Data.

Result





B -- REPLACE BRAKE ACTUATOR
A -- REPLACE SKID CONTROL ECU