Toyota 4Runner: Stop Light Control Relay Malfunction (C1380)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Stop Light Control Relay Malfunction (C1380)

DESCRIPTION

Upon receiving the hill-start assist control operating signal from the master cylinder solenoid (skid control ECU), the Stop light control relay (Stop light switch assembly) contact turns on and the stop lights come on.

DTC No.	DTC Detection Condition	Trouble Area
C1380	When the voltage at the IG1 terminal is 9.5 V or more and the stop light control relay drive output (STPO) is ON, a signal is not input to the STP2 terminal for 5 seconds or more. When the voltage at the IG1 terminal is 9.5 V or more and the stop light control relay drive output (STPO) is OFF, the signal at the STP terminal is different from the input signal at the STP2 for 5 seconds or more.	Stop light control relay (Stop light switch assembly) Stop light control relay (Stop light switch assembly) circuit Master cylinder solenoid (Skid control ECU)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

When DTC C1425 is output together with DTC C1380, inspect and repair the trouble areas indicated by DTC C1425 first (See page ).

PROCEDURE

1.	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

INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

2.	READ VALUE USING TECHSTREAM (STOP LIGHT SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Stop Light SW	Stop light switch assembly / ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Stop Light SW

Stop light switch assembly / ON or OFF

ON: Brake pedal depressed

OFF: Brake pedal released

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

OK:

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

GO TO STEP 8

3.	PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT RELAY)

(a) Select the Active Test on the Techstream (See page ).

ABS/VSC/TRAC

Tester Display	Test Part	Control Range	Diagnostic Note
Stop Light Relay	Stop light control relay (Stop light switch assembly)	Relay (Switch) ON/OFF	Stop lights come on

(b) Perform the Active Test of the stop light control relay (stop light switch assembly) using the Techstream.

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Stop Light Relay Output	Stop light control relay (Stop light switch assembly) output / ON or OFF	ON: Relay output on OFF: Relay output off	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Stop Light Relay Output

Stop light control relay (Stop light switch assembly) output / ON or OFF

ON: Relay output on

OFF: Relay output off

(d) Check for stop light control relay (stop light switch assembly) operation using the Data List and stop light operation by performing an Active Test.

Result	Proceed to
Data List content and stop light operation are normal.	A
Data List content and stop light operation are abnormal or Data List content is normal but stop lights do not turn on or off.	B

GO TO STEP 6

4.	CHECK HARNESS AND CONNECTOR (STP2 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.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A6-45 (STP2) - Body ground	Stop light switch assembly ON (Brake pedal depressed)	11 to 14 V
A6-45 (STP2) - Body ground	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)

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT)

5.	RECONFIRM DTC

(a) Reconnect the skid control ECU connector.

(b) Clear the DTCs (See page ).

(d) Perform a road test.

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

Result	Proceed to
DTC C1380 is not output.	A
DTC C1380 is output.	B

CHECK FOR INTERMITTENT PROBLEMS

REPLACE MASTER CYLINDER SOLENOID

6.	CHECK STOP LIGHT SWITCH ASSEMBLY

(a) Check the stop light control relay (stop light switch assembly) (See page ).

OK:

The stop light control relay (stop light switch assembly) is normal.

REPLACE STOP LIGHT SWITCH ASSEMBLY

7.	CHECK HARNESS AND CONNECTOR (STPO TERMINAL)

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

(b) Disconnect the A6 skid control ECU connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A6-16 (STPO) - Body ground	Always	11 to 14 V

Text in Illustration

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

REPLACE MASTER CYLINDER SOLENOID

REPAIR OR REPLACE HARNESS OR CONNECTOR (STPO 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.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A6-7 (STP) - Body ground	Stop light switch assembly ON (Brake pedal depressed)	11 to 14 V
A6-7 (STP) - Body ground	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)

REPLACE MASTER CYLINDER SOLENOID

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

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