Lexus ES: Stop Light Control Relay Malfunction (C1380)

Lexus ES (XZ10) Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System (for Hv Model) / Stop Light Control Relay Malfunction (C1380)

DESCRIPTION

When any of the following conditions are met, the skid control ECU (brake booster with master cylinder assembly) sets the drive output (STPO) ON which operates the stop light control relay (stop light switch assembly) and turns on the stop lights.

Illumination Conditions:

Pre-collision brake is operating.
The dynamic radar cruise control system is operating and is applying the brakes.
Secondary collision brake is operating.
Brake hold is operating.
The parking brake is engaged while the vehicle is being driven.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1380	Stop Light Control Relay Malfunction	761 762	INF Code: 761 When terminal IG1 voltage is 9.5 V or more, stop light drive output (STPO) is on and STP2 is off for 2 seconds or more. INF Code: 762 When terminal IG1 voltage is 9.5 V or more, stop light drive output (STPO) is off and the input signals for STP and STP2 differ for 5 seconds or more.	Wire harness or connector Stop light switch assembly Skid control ECU (brake booster with master cylinder assembly) Rear combination light assembly LH Rear combination light assembly RH Rear light assembly LH Rear light assembly RH Center stop light set Hybrid vehicle control ECU Certification ECU (smart key ECU assembly)	Does not come on	VSC DTC

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

Note

C1380

Stop Light Control Relay Malfunction

761

762

INF Code: 761
- When terminal IG1 voltage is 9.5 V or more, stop light drive output (STPO) is on and STP2 is off for 2 seconds or more.
INF Code: 762
- When terminal IG1 voltage is 9.5 V or more, stop light drive output (STPO) is off and the input signals for STP and STP2 differ for 5 seconds or more.

Wire harness or connector
Stop light switch assembly
Skid control ECU (brake booster with master cylinder assembly)
Rear combination light assembly LH
Rear combination light assembly RH
Rear light assembly LH
Rear light assembly RH
Center stop light set
Hybrid vehicle control ECU
Certification ECU (smart key ECU assembly)

Does not come on

VSC DTC

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".
Click here
Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (STP, STPO AND STP2 TERMINAL)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less
A45-22 (STPO) - Body ground	Always	11 to 14 V
A45-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-37 (STP2) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

Result	Proceed to
All terminal voltages are normal.	A
Only STP2 terminal voltage abnormal.	B
Only STPO terminal voltage abnormal.	C
Only STP terminal voltage abnormal.	D
STPO terminal and STP terminal voltage abnormal.	E

GO TO STEP 5

GO TO STEP 9

GO TO STEP 10

GO TO STEP 17

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

(a) Reconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.

(b) Select the Active Test on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Stop Light Relay	Stop light control relay (Stop light switch assembly)	Relay ON/OFF	-

Chassis > ABS/VSC/TRAC > Active Test

Tester Display
Stop Light Relay

OK:

Stop lights turn on/off in accordance with the Active Test.

GO TO STEP 4

3.	RECONFIRM DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Select the Active Test on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Stop Light Relay	Stop light control relay (Stop light switch assembly)	Relay ON/OFF	-

Chassis > ABS/VSC/TRAC > Active Test

Tester Display
Stop Light Relay

(d) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

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

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

USE SIMULATION METHOD TO CHECK

4.	INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

(a) Select the Active Test on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Stop Light Relay	Stop light control relay (Stop light switch assembly)	Relay ON/OFF	-

Chassis > ABS/VSC/TRAC > Active Test

Tester Display
Stop Light Relay

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A80-4 (ACC) - Body ground	Active Test is on	1.5 V or less

*a	Component with harness connected (Stop Light Switch Assembly)

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

5.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - HYBRID VEHICLE CONTROL ECU)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the A32 hybrid vehicle control ECU connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-37 (STP2) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE HYBRID VEHICLE CONTROL ECU

6.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - SMART KEY ECU ASSEMBLY)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the N9 certification ECU (smart key ECU assembly) connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-37 (STP2) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE SMART KEY ECU ASSEMBLY

7.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the A80 stop light switch assembly connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-37 (STP2) - Body ground	Always	1.5 V or less

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A45-37 (STP2) - A80-3 (L)	Always	Below 1 Ω
A45-37 (STP2) or A80-3 (L) - Body ground	Always	10 kΩ or higher

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

OK:

The connector is securely connected.

(b) Disconnect the A80 stop light switch assembly connector.

OK:

No deformation or corrosion.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A45-22 (STPO) - A80-4 (ACC)	Always	Below 1 Ω

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

10.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - REAR COMBINATION LIGHT ASSEMBLY LH)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the R9 rear combination light assembly LH connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE REAR COMBINATION LIGHT ASSEMBLY LH

11.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - REAR COMBINATION LIGHT ASSEMBLY RH)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the R8 rear combination light assembly RH connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE REAR COMBINATION LIGHT ASSEMBLY RH

12.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - REAR LIGHT ASSEMBLY LH)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the R11 rear light assembly LH connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE REAR LIGHT ASSEMBLY LH

13.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - REAR LIGHT ASSEMBLY RH)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the R10 rear light assembly RH connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE REAR LIGHT ASSEMBLY RH

14.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - CENTER STOP LIGHT SET)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the N52 center stop light set connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A45-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE CENTER STOP LIGHT SET

15.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Disconnect the A80 stop light switch assembly connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-12 (STP) - Body ground	Always	1.5 V or less

REPAIR OR REPLACE HARNESS OR CONNECTOR

16.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A80-1 (OUT) - A45-12 (STP)	Always	Below 1 Ω
A80-1 (OUT) or A45-12 (STP) - Body ground	Always	10 kΩ or higher

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

17.	CHECK STOP LIGHT SWITCH ASSEMBLY POWER SOURCE CIRCUIT

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

OK:

The connector is securely connected.

*a	Front view of wire harness connector (to Stop Light Switch Assembly)

(b) Disconnect the A80 stop light switch assembly connector.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A80-7 (B) - Body ground	Always	11 to 14 V

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A80-2 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

18.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A45-22 (STPO) or A80-4 (ACC) - Body ground	Always	10 kΩ or higher

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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