Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Stop Lamp Relay Actuator Stuck Off (C13807F)

DESCRIPTION

Refer to DTC C13807E.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C13807F	Stop Lamp Relay Actuator Stuck Off	Either of the following is detected: When the IG1 terminal voltage exceeds 10 V and the +BS terminal voltage is from 9.5 to 17.4 V, stop light drive output (STPO) is ON, STP is OFF and STP2 is OFF continuously for 2 seconds or more. When the IG1 terminal voltage exceeds 10 V and the +BS terminal voltage is 9.5 V or higher, stop light drive output (STPO) is OFF, STP is ON and STP2 is OFF continuously for 5 seconds or more.	Wire harness and connector Semiconductor PWR integration ECU Skid control ECU (Brake actuator assembly) Rear light assembly LH Rear combination light assembly LH Rear light assembly RH Rear combination light assembly RH Center stop light assembly

DTC Detection Conditions: C13807F

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	IG1 terminal voltage exceeds 10 V and +BS terminal voltage is from 9.5 to 17.4 V	○	-
	IG1 terminal voltage exceeds 10 V and +BS terminal voltage is 9.5 V or higher	-	○
Malfunction Status	Stop light drive output (STPO) is ON, STP is OFF and STP2 is OFF	○	-
	Stop light drive output (STPO) is OFF, STP is ON and STP2 is OFF	-	○
Detection Time		2 seconds or more.	5 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 C13807E.

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CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake actuator assembly), perform "Calibration".

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PROCEDURE

1.	CHECK STOP LIGHT OPERATION

(a) Check that the stop lights come on when the brake pedal is depressed.

OK:

The stop lights illuminate.

NG

GO TO STEP 6

OK

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

(a) Connect the Techstream to the DLC3.

(b) Enter the following menus: Chassis / Brake/EPB / Active Test.

Chassis > Brake/EPB > Active Test

Tester Display	Measurement Item	Control Range	Restrict Condition	Diagnostic Note
Stop Lamp Relay	Semiconductor PWR integration ECU (STPO terminal output)	OFF / ON	Vehicle condition: Vehicle stopped HINT: To protect this Actuator and Solenoid, this test will only last 5 seconds.	-

Chassis > Brake/EPB > Active Test

Tester Display
Stop Lamp Relay

(c) According to the display on the Techstream, perform the Active Test and check the operation of the stop lights.

OK:

Stop lights turn on in accordance with the Active Test.

NG

GO TO STEP 4

OK

3.	CHECK HARNESS AND CONNECTOR (STOP LIGHT SIGNAL INPUT CIRCUIT)

(a) Turn the engine 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 connectors.

OK:

The connector is securely connected.

(c) Disconnect the A41 skid control ECU (brake actuator assembly) connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A41-37 (STP2) - Body ground	Brake pedal depressed	11 to 14 V

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (STOP LIGHT ILLUMINATION OUTPUT CIRCUIT)

(a) Turn the engine 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 connectors.

OK:

The connector is securely connected.

(c) Disconnect the A41 skid control ECU (brake actuator assembly) connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A41-32 (STPO) - Body ground	Engine switch on (IG)	11 to 14 V

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

5.	CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BRAKE ACTUATOR ASSEMBLY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the 1D semiconductor PWR integration ECU connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1D-3 (ACC) - A41-32 (STPO)	Always	Below 1 Ω

OK

REPLACE SEMICONDUCTOR PWR INTEGRATION ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	READ VALUE USING TECHSTREAM (STOP LIGHT RELAY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the S31 rear combination light assembly LH connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

(f) Connect the Techstream to the DLC3.

(g) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Relay	Semiconductor PWR integration ECU (STP2 terminal input)	OFF / ON	OFF: Semiconductor PWR integration ECU (STP2 terminal input) OFF ON: Semiconductor PWR integration ECU (STP2 terminal input) ON	HINT: The stop light state is determined using the voltage at terminal STP2

Chassis > Brake/EPB > Data List

Tester Display
Stop Light Relay

(h) With the brake pedal released, check the value of Data List item "Stop Light Relay".

Result	Proceed to
The value of Data List item "Stop Light Relay" is "OFF"	A
The value of Data List item "Stop Light Relay" is "ON"	B

A

GO TO LIGHTING SYSTEM (REAR COMBINATION LIGHT ASSEMBLY LH (STOP LIGHT CIRCUIT))

B

7.	READ VALUE USING TECHSTREAM (STOP LIGHT RELAY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the S33 rear combination light assembly RH connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

(f) Connect the Techstream to the DLC3.

(g) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Relay	Semiconductor PWR integration ECU (STP2 terminal input)	OFF / ON	OFF: Semiconductor PWR integration ECU (STP2 terminal input) OFF ON: Semiconductor PWR integration ECU (STP2 terminal input) ON	HINT: The stop light state is determined using the voltage at terminal STP2

Chassis > Brake/EPB > Data List

Tester Display
Stop Light Relay

(h) With the brake pedal released, check the value of Data List item "Stop Light Relay".

Result	Proceed to
The value of Data List item "Stop Light Relay" is "OFF"	A
The value of Data List item "Stop Light Relay" is "ON"	B

A

GO TO LIGHTING SYSTEM (REAR COMBINATION LIGHT ASSEMBLY RH (STOP LIGHT CIRCUIT))

B

8.	READ VALUE USING TECHSTREAM (STOP LIGHT RELAY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the Z21 rear light assembly LH connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

(f) Connect the Techstream to the DLC3.

(g) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Relay	Semiconductor PWR integration ECU (STP2 terminal input)	OFF / ON	OFF: Semiconductor PWR integration ECU (STP2 terminal input) OFF ON: Semiconductor PWR integration ECU (STP2 terminal input) ON	HINT: The stop light state is determined using the voltage at terminal STP2

Chassis > Brake/EPB > Data List

Tester Display
Stop Light Relay

(h) With the brake pedal released, check the value of Data List item "Stop Light Relay".

Result	Proceed to
The value of Data List item "Stop Light Relay" is "OFF"	A
The value of Data List item "Stop Light Relay" is "ON"	B

A

GO TO LIGHTING SYSTEM (REAR LIGHT ASSEMBLY LH (STOP LIGHT CIRCUIT))

B

9.	READ VALUE USING TECHSTREAM (STOP LIGHT RELAY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the Z20 rear light assembly RH connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

(f) Connect the Techstream to the DLC3.

(g) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Relay	Semiconductor PWR integration ECU (STP2 terminal input)	OFF / ON	OFF: Semiconductor PWR integration ECU (STP2 terminal input) OFF ON: Semiconductor PWR integration ECU (STP2 terminal input) ON	HINT: The stop light state is determined using the voltage at terminal STP2

Chassis > Brake/EPB > Data List

Tester Display
Stop Light Relay

(h) With the brake pedal released, check the value of Data List item "Stop Light Relay".

Result	Proceed to
The value of Data List item "Stop Light Relay" is "OFF"	A
The value of Data List item "Stop Light Relay" is "ON"	B

A

GO TO LIGHTING SYSTEM (REAR LIGHT ASSEMBLY RH (STOP LIGHT CIRCUIT))

B

10.	READ VALUE USING TECHSTREAM (STOP LIGHT RELAY)

(a) Turn the engine switch off.

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

OK:

The connector is securely connected.

(c) Disconnect the v1 center stop light assembly connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Turn the engine switch on (IG).

(f) Connect the Techstream to the DLC3.

(g) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Relay	Semiconductor PWR integration ECU (STP2 terminal input)	OFF / ON	OFF: Semiconductor PWR integration ECU (STP2 terminal input) OFF ON: Semiconductor PWR integration ECU (STP2 terminal input) ON	HINT: The stop light state is determined using the voltage at terminal STP2

Chassis > Brake/EPB > Data List

Tester Display
Stop Light Relay

(h) With the brake pedal released, check the value of Data List item "Stop Light Relay".

Result	Proceed to
The value of Data List item "Stop Light Relay" is "OFF"	A
The value of Data List item "Stop Light Relay" is "ON"	B

A

REPLACE CENTER STOP LIGHT ASSEMBLY

B

11.	CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BRAKE ACTUATOR ASSEMBLY)

(a) Turn the engine 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 connectors.

OK:

The connector is securely connected.

(c) Disconnect the A41 skid control ECU (brake actuator assembly) connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A41-37 (STP2) - Body ground	Brake pedal depressed	11 to 14 V

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

12.	CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BRAKE ACTUATOR ASSEMBLY)

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

OK:

The connector is securely connected.

(b) Disconnect the 1D semiconductor PWR integration ECU connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

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
1D-10 (STP) - A41-11 (STP)	Always	Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

13.	CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BRAKE ACTUATOR ASSEMBLY)

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

OK:

The connector is securely connected.

(b) Disconnect the 1F semiconductor PWR integration ECU connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

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
1F-9 (OUT) - A41-37 (STP2)	Always	Below 1 Ω
1F-9 (OUT) or A41-37 (STP2) - Body ground and other terminals	Always	10 kΩ or higher

OK

REPLACE SEMICONDUCTOR PWR INTEGRATION ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR