Toyota CH-R Service Manual: Stop Light Switch OFF Stuck Malfunction (C1426)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives stop light switch signals and uses them to determine whether or not the brakes are applied.

The skid control ECU (brake actuator assembly) has a detection circuit that it uses to detect a short in the stop light input line or the ground line of the stop light circuit with the stop light switch on (brake pedal depressed).

If the skid control ECU (brake actuator assembly) detects a short in this circuit, it will store this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C1426	Stop Light Switch OFF Stuck Malfunction	Either of the following is detected: With the stop light switch off, the stop light switch is judged to be on based on the master cylinder pressure value for 3 seconds or more. With the stop light switch off, the master cylinder pressure is more than 8 MPa (81.6 kgf/cm2, 1160 psi) for 3 seconds or more.	Wire harness or connector Stop light switch assembly Skid Control ECU (brake Actuator Assembly)

DTC Detection Conditions: C1426

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	-	-	-
Malfunction Status	With the stop light switch off, the stop light switch is judged to be on based on the master cylinder pressure value.	○	-
	With the stop light switch off, the master cylinder pressure is more than 8 MPa (81.6 kgf/cm2, 1160 psi).	-	○
Detection Time		3 seconds or more	3 seconds or more
Number of Trips		1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

Refer to DTC C1249.

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CAUTION / NOTICE / HINT

PROCEDURE

1.	CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

(a) Check the brake pedal height installation.

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(b) Check the stop light switch assembly installation.

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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 the 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 7

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.

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Chassis > ABS/VSC/TRAC/EPB > Data List

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	-

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display
Stop Light SW

(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 5

OK

4.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC/EPB > Clear DTCs

(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 output.

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Chassis > ABS/VSC/TRAC/EPB > Trouble Codes

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 before replacing parts.

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A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

5.	CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(a) Turn the ignition switch off.

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

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

(c) Disconnect the A42 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A42-44 (STP2) - Body ground	Stop light switch ON (Brake pedal depressed)	11 to 14 V*

HINT:

*: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

OK

6.	CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A42-46 (GND1) - Body ground Always Below 1 Ω HINT: If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts. Click here

*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 (GND1 CIRCUIT)

7.	INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Check the stop light switch assembly.

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OK:

The stop light switch assembly is normal.

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

8.	CHECK HARNESS AND CONNECTOR (STP TERMINAL)

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

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

(b) Disconnect the A42 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A42-44 (STP2) - Body ground	Stop light switch ON (Brake pedal depressed)	11 to 14 V*
A42-44 (STP2) - Body ground	Stop light switch OFF (Brake pedal released)	Below 1.5 V

HINT:

*: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

OK

9.	RECONFIRM DTC

(a) Reconnect the A42 skid control ECU (brake actuator assembly) connector.

(b) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC/EPB > Clear DTCs

(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 output.

Click here

Chassis > ABS/VSC/TRAC/EPB > Trouble Codes

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 before replacing parts.

Click here

A

INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

B

REPLACE BRAKE ACTUATOR ASSEMBLY