Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Stop Light Control Relay Malfunction (C1380)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System(for Hv Model) / Stop Light Control Relay Malfunction (C1380)

DESCRIPTION

When the skid control ECU (brake booster with master cylinder assembly) applies the brakes after receiving a brake request signal from the pre-collision system, dynamic radar cruise control system, secondary collision brake system or brake hold control system, the skid control ECU (brake booster with master cylinder assembly) operates the stop light control relay (stop light switch assembly) to illuminate the stop lights.

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)
Vehicle approaching speaker controller

Does not come on

VSC DTC

*: w/ Cornering Light

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 A35 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less
A35-22 (STPO) - Body ground	Always	11 to 14 V
A35-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-37 (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 18

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

(a) Reconnect the A35 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
A33-4 (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 A23 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
A35-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-37 (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 K10 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
A35-37 (STP2) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-37 (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 A33 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
A35-37 (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
A35-37 (STP2) - A33-3 (L)	Always	Below 1 Ω
A35-37 (STP2) or A33-3 (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 A33 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
A35-22 (STPO) - A33-4 (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 P10 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (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 P9 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

Result	Proceed to
OK	A
NG (w/o Cornering Light)	B
NG (w/ Cornering Light)	C

REPLACE REAR COMBINATION LIGHT ASSEMBLY RH

GO TO STEP 14

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 P12 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (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 P11 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (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 K41 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (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 - VEHICLE APPROACHING SPEAKER CONTROLLER)

(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 G38 vehicle approaching speaker controller 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
A35-12 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	11 to 14 V
A35-12 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	1.5 V or less

REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER

16.	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 A33 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
A35-12 (STP) - Body ground	Always	1.5 V or less

REPAIR OR REPLACE HARNESS OR CONNECTOR

17.	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
A33-1 (OUT) - A35-12 (STP)	Always	Below 1 Ω
A33-1 (OUT) or A35-12 (STP) - Body ground	Always	10 kΩ or higher

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

18.	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 A33 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
A33-7 (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
A33-2 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

19.	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
A35-22 (STPO) or A33-4 (ACC) - Body ground	Always	10 kΩ or higher

REPLACE STOP LIGHT SWITCH ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

Increasing Pressure Solenoid (FR) (C1352-C1359)

Abnormal Leak in Accumulator (C1391)

See More:

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Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Stop Light Control Relay Malfunction (C1380)

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See More:

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