Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018KEP
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1425; Open in Stop Light Switch Circuit; 2018 - 2020 MY Sienna [11/2017 -        ]

DTC

C1425

Open in Stop Light Switch Circuit

DESCRIPTION

The skid control ECU (brake actuator assembly) detects the brake operating conditions through a signal transmitted by the stop light switch assembly.

The skid control ECU (brake actuator assembly) incorporates a circuit to detect an open circuit. This DTC is output when an open circuit is detected in the stop light signal input line.

DTC No.

DTC Detection Condition

Trouble Area

C1425

When voltage at terminal +BS is 9.5 to 17.4 V, open circuit occurs between STP terminal circuits A and B for 0.3 seconds or more.
  • Wire harness or connector
  • Stop light switch assembly
  • Skid control ECU (brake actuator assembly)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: CALIBRATION ).
  • Inspect the fuses for circuits related to this system before performing the following inspection 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
NG

GO TO STEP 4

OK

2.

READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(e) Select the Data List using the Techstream (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DATA LIST / ACTIVE TEST ).

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

-

(f) 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.

NG

GO TO STEP 9

OK

3.

RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR ).

(c) Turn the ignition switch off.

(d) Start the engine.

(e) Depress the brake pedal several times to test the stop light circuit.

(f) Check if the same DTC is output (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR ).

Result

Proceed to

DTC C1425 is not output.

A

DTC C1425 is output.

B

HINT:

If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: PROBLEM SYMPTOMS TABLE ).

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

4.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) for Bulb Type Stop Light

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

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

1 - 2

Switch pin released

Below 1 Ω

Switch pin pushed in

10 kΩ or higher

Text in Illustration

*a

Component without harness connected

(Stop Light Switch Assembly)

(b) for LED Type Stop Light

(1) Reconnect the stop light switch assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A59-2 (L) - A59-3 (GND)

Switch pin released

8 to 14 V

Switch pin pushed in

Below 1.5 V

Text in Illustration

*a

Component with harness connected

(Stop Light Switch Assembly)

Result

Result

Proceed to

OK (w/ Toyota Safety Sense P)

A

OK (w/o Toyota Safety Sense P)

B

NG

C
B

GO TO STEP 7

C

REPLACE STOP LIGHT SWITCH ASSEMBLY

A

5.

CHECK HARNESS AND CONNECTOR (SWITCH INPUT TERMINAL)

(a) Turn the ignition switch off.

(b) Remove the STOP LP relay.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

STOP LP relay terminal 4 - Body ground

Stop light switch assembly ON (Brake pedal depressed)

8 to 14 V

STOP LP relay terminal 4 - Body ground

Stop light switch assembly OFF (Brake pedal released)

Below 1.5 V

Text in Illustration

*1

Engine Room Relay Block

*2

STOP LP Relay Holder
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (SWITCH INPUT CIRCUIT)
OK

6.

INSPECT STOP LP RELAY

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 - 4

Voltage is not applied between terminals 1 and 2

Below 1 Ω

3 - 4

Voltage is applied between terminals 1 and 2

10 kΩ or higher

Text in Illustration

*1

STOP LP Relay
NG

REPLACE STOP LP RELAY
OK

7.

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.

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A75-35 (STP) - Body ground

Stop light switch assembly ON (Brake pedal depressed)

8 to 14 V

A75-35 (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))

HINT:

  • If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: PROBLEM SYMPTOMS TABLE ).
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
OK

8.

RECONFIRM DTC

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

(b) Disconnect the A75 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A75-35 (STP) - Body ground

Stop light switch assembly on (Brake pedal depressed)

8 to 14 V

A75-35 (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))

(d) Turn the ignition switch off.

(e) Reconnect the A75 skid control ECU (brake actuator assembly) connector.

(f) Clear the DTCs (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR ).

(g) Turn the ignition switch off.

(h) Start the engine.

(i) Check if the same DTC is output (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

DTC C1425 is not output.

A

DTC C1425 is output.

B

HINT:

  • If the lighting system is normal but the DTC is still output, replace the skid control ECU (brake actuator assembly).
  • If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: PROBLEM SYMPTOMS TABLE ).
A

USE SIMULATION METHOD TO CHECK

B

INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

9.

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.

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A75-35 (STP) - Body ground

Stop light switch assembly ON (Brake pedal depressed)

8 to 14 V

A75-35 (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))

HINT:

If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: PROBLEM SYMPTOMS TABLE ).
OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)