Toyota Tacoma (2015-2018) Service Manual: Master Cylinder Pressure Sensor Zero Point High Malfunction (C1422,C1456)

Toyota Tacoma (2015-2018) Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Master Cylinder Pressure Sensor Zero Point High Malfunction (C1422,C1456)

DESCRIPTION

Refer to DTCs C1421, C1423, C1424, C1455, C1457 and C1458 (See page ).

DTC Code	DTC Detection Condition	Trouble Area
C1422	When the stop light switch is off, the PM/C1 terminal voltage is 0.86 V or higher for 5 seconds or more.	Stop light switch Stop light switch circuit Master cylinder pressure sensor circuit Master cylinder solenoid (Master cylinder pressure sensor)
C1456	When the stop light switch is off, the PCTRL terminal voltage is 0.86 V or higher for 5 seconds or more.	Stop light switch Stop light switch circuit Master cylinder pressure sensor circuit Master cylinder solenoid (Master cylinder pressure sensor)

WIRING DIAGRAM

Refer to DTC C1380 (See page CAUTION / NOTICE / HINT ).

CAUTION / NOTICE / HINT

NOTICE:

When replacing the master cylinder solenoid, perform calibration (See page HINT: ).

HINT:

When DTC C1425 is output together with DTC C1422 inspect and repair the trouble areas indicated by DTC C1425 first (See page PROCEDURE ).

PROCEDURE

1.	CHECK STOP LIGHT SWITCH OPERATION

(See page )

GO TO STEP 6

2.	READ VALUE USING TECHSTREAM (STOP LIGHT SW AND MASTER CYLINDER SENSOR)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

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	-
Master Cylinder Sensor	Master cylinder pressure sensor reading/ Min.: 0 V, Max.: 5 V	0.3 to 0.9 V: When brake pedal is released	Reading increases when brake pedal is depressed.

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

Master Cylinder Sensor

Master cylinder pressure sensor reading/ Min.: 0 V, Max.: 5 V

0.3 to 0.9 V: When brake pedal is released

Reading increases when brake pedal is depressed.

Standard:

Master cylinder pressure sensor reading is 0.86 V or less at the instant the stop light switch changes from off to on.

GO TO STEP 4

3.	RECONFIRM DTC

(a) Clear the DTCs (See page (b) Start the engine. ).

(b) Start the engine.

(c) Drive the vehicle at a speed of 40 km/h (25 mph) or more and perform a braking test (decelerate the vehicle by depressing the brake pedal).

(d) Check if the same DTC is output (See page ).

Result

Result	Proceed to
DTC C1422 and C1456 is not output	A
DTC C1422 or C1456 is output	B

USE SIMULATION METHOD TO CHECK

REPLACE MASTER CYLINDER SOLENOID

4.	CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

(a) Turn the ignition switch off.

(b) Check the brake pedal height and stop light switch installation (See page OK: ).

OK:

The brake pedal height and stop light switch installation are normal.

ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH

5.	CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(See page )

REPLACE MASTER CYLINDER SOLENOID

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

(See page )

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

7.	INSPECT STOP LIGHT SWITCH ASSEMBLY

(See page )

REPLACE STOP LIGHT SWITCH ASSEMBLY

8.	CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - STOP LP CTRL RELAY)

(See page )

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	INSPECT LP CTRL RELAY

(See page )

REPLACE STOP LP CTRL RELAY

10.	CHECK HARNESS AND CONNECTOR (REAR COMBINATION LIGHT ASSEMBLY, HIGH MOUNTED STOP LIGHT ASSEMBLY - STOP LP CTRL RELAY)

(See page )

REPAIR OR REPLACE HARNESS OR CONNECTOR

GO TO STEP 12

11.	INSPECT REAR COMBINATION LIGHT ASSEMBLY

(See page )

USE SIMULATION METHOD TO CHECK

REPLACE REAR COMBINATION LIGHT ASSEMBLY

12.	INSPECT CENTER STOP LIGHT BULB

(See page )

USE SIMULATION METHOD TO CHECK

REPLACE CENTER STOP LIGHT BULB

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