Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Stop Light Switch OFF Stuck Malfunction (C1426)

DESCRIPTION

The skid control ECU (brake actuator assembly) inputs the stop light signal and brake operation condition. When the brake pedal is depressed and the stop light switch signal is not input, C1426 is output.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1426

Stop Light Switch OFF Stuck Malfunction

When voltage at terminal +BS is 9.5 V or higher, vehicle is driven and brake pedal is operated, stop light switch signal is not input.

  • Wire harness or connector
  • STOP fuse
  • Stop light switch assembly
  • Skid Control ECU (Brake actuator assembly)

WIRING DIAGRAM

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

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information (See page ).
  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

(a) Check the brake pedal height installation (See page (b) Check the stop light switch assembly installation (See page (b) Check the stop light switch assembly installation (See page ).

(b) Check the stop light switch assembly installation (See page OK: ).

OK:

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

HINT:

If the on/off status of the stop light switch assembly and pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and switch before inspecting the input signals and other related parts.

NG

ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY

OK

2.

CHECK STOP LIGHT OPERATION

(a) Check that all stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

OK:

Condition

Illumination Condition

Brake pedal depressed.

On

Brake pedal released.

Off

NG

GO TO STEP 5

OK

3.

READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Select the Data List using the Techstream (See page ABS/VSC/TRAC ABS/VSC/TRAC ).

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

-

(d) Check that the stop light switch display observed on the Techstream changes according to brake pedal operation.

OK:

The Techstream displays ON or OFF according to brake pedal operation.

NG

GO TO STEP 8

OK

4.

RECONFIRM DTC

(a) Turn the ignition switch off.

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

(c) Start the engine.

(d) Depress the brake pedal several times to test the stop light circuit.

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

Result

Result

Proceed to

DTC C1426 is not output.

A

DTC C1426 is output.

B

HINT:

If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step (See page ).

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

5.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Check the stop light switch assembly (See page OK: ).

OK:

The stop light switch assembly is normal.

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

6.

CHECK HARNESS AND CONNECTOR (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.

(c) Disconnect the S1 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

S1-35 (STP) - Body ground

Stop light switch assembly on (Brake pedal depressed)

8 to 14 V

Stop light switch assembly off (Brake pedal released)

Below 1.5 V

Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

OK

7.

RECONFIRM DTC

(a) Reconnect the S1 skid control ECU (brake actuator assembly) connector.

(b) Clear the DTCs (See page ). (c) Turn the ignition switch off. ).

(c) Turn the ignition switch off.

(d) Start the engine.

(e) Depress the brake pedal several times to test the stop light circuit.

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

Result

Result

Proceed to

DTC C1426 is not output.

A

DTC C1426 is output.

B

A

USE SIMULATION METHOD TO CHECK

B

INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

8.

CHECK HARNESS AND CONNECTOR (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.

(c) Disconnect the S1 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

S1-35 (STP) - Body ground

Stop light switch assembly on (Brake pedal depressed)

8 to 14 V

Stop light switch assembly off (Brake pedal released)

Below 1.5 V

Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

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