Toyota Tacoma (2015-2018) Service Manual: Stop Light Control Relay Malfunction (C1380)

Toyota Tacoma (2015-2018) Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Vacuum Brake Booster) / Stop Light Control Relay Malfunction (C1380)

DESCRIPTION

The skid control ECU (brake actuator assembly) inputs the stop light switch signal and detect the status of the brake operation.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C1380	Stop Light Control Relay Malfunction	Either of the following is detected: When the voltage at the +BS terminal is 9.5 V or higher and the stop light control relay drive output (STPO) is on, a signal has not been input to the STP terminal for 2 seconds or more. When the voltage at the +BS terminal is 9.5 V or higher and the stop light control relay drive output (STPO) is off, the signal at the STP is different from the input signal at the STP2 for 2 seconds or more.	IG NO. 1 fuse STOP fuse Stop light switch circuit STOP Relay Stop light control relay circuit Skid control ECU (Brake actuator assembly)

HINT:

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), 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 ).

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 STOP LIGHT CIRCUIT

2.	CHECK HARNESS AND CONNECTOR (STP TERMINAL)

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

(b) Turn the ignition switch off.

(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
S1-35 (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 [Brake Actuator Assembly])

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

3.	CHECK HARNESS AND CONNECTOR (STP2 TERMINAL)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
S1-7 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	8 to 14 V
S1-7 (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 [Brake Actuator Assembly])

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT)

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

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

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.

ABS/VSC/TRAC

Tester Display	Measurement Item	Control Range	Diagnostic Note
Stop Light Relay	Stop Light Relay	Relay ON/OFF	Stop lights come on Vehicle condition: Vehicle stopped

Tester Display

Measurement Item

Control Range

Diagnostic Note

Stop Light Relay

Relay ON/OFF

Stop lights come on

Vehicle condition: Vehicle stopped

(f) While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List.

ABS/VSC/TRAC

Tester Display	Measurement Item	Normal Condition	Diagnostic Note
Stop Light Relay	Stop Light Relay	OFF: Relay output off (Stop lights off) ON: Relay output on (Stop lights on)	-

Tester Display

Measurement Item

Normal Condition

Diagnostic Note

Stop Light Relay

OFF: Relay output off (Stop lights off)

ON: Relay output on (Stop lights on)

Result

Result	Proceed to
When Active Test performed, Data List item changes between ON and OFF and stop lights turn on and off	A
When Active Test performed, Data List item changes between ON and OFF, but stop lights do not turn on	B

GO TO STEP 6

5.	RECONFIRM DTC

(a) Turn the ignition switch off.

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

(d) Perform a road test.

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

Result

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

USE SIMULATION METHOD TO CHECK

REPLACE BRAKE ACTUATOR ASSEMBLY

6.	INSPECT STOP LIGHT CONTROL RELAY (STOP RELAY)

(a) Remove the STOP relay from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Condition
3 - 4	Battery voltage not applied	Below 1 Ω
3 - 4	Battery voltage applied to terminal 1 and 2	10 kΩ or higher
3 - 5	Battery voltage not applied	10 kΩ or higher
3 - 5	Battery voltage applied to terminal 1 and 2	Below 1 Ω

Text in Illustration

*1	STOP Relay

REPLACE STOP LIGHT CONTROL RELAY (STOP RELAY)

7.	CHECK TERMINAL VOLTAGE (STOP LIGHT POWER SOURCE TERMINAL)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
5 - Body ground	Always	11 to 14 V
1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Component without Stop Light Control Relay (STOP Relay) (Engine Room Relay Block and Junction Block)

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK HARNESS AND CONNECTOR (STPO TERMINAL)

(a) Install the stop light control relay (STOP Relay).

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

(d) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
S1-26 (STPO) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

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

REPLACE BRAKE ACTUATOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (STPO CIRCUIT)

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