Toyota Avalon Service & Repair Manual: Open in Stop Light Switch Circuit (C1425)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives stop light switch assembly signals and uses them to determine whether or not the brakes are applied.

The skid control ECU (brake actuator assembly) has a detection circuit that it uses to detect an open in the stop light input line.

If the skid control ECU (brake actuator assembly) detects an open in this circuit, it will store this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1425

Open in Stop Light Switch Circuit

An open in the stop light switch assembly input line continues for 3 seconds or more.

  • Wire harness or connector
  • Stop light switch assembly
  • Skid control ECU (brake actuator assembly)

WIRING DIAGRAM

Ref to DTC C1249.

Click here

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (BS1 VOLTAGE VALUE)

(a) Connect the Techstream to the DLC3.

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

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

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

BS1 Voltage Value

+BS voltage value

Min.: 0.00 V, Max.: 20.00 V

-

Changes in proportion to battery voltage

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display

BS1 Voltage Value

(d) Take a note of the +BS voltage value.

HINT:

The noted +BS voltage value is used in a later step.

NEXT

2.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly.

Click here

OK:

The stop light switch assembly is normal.

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

3.

READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

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

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

Chassis > ABS/VSC/TRAC/EPB > Data List

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

-

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display

Stop Light SW

(d) Check that the stop light switch assembly display 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 5

OK

4.

RECONFIRM DTC

(a) Clear the DTCs.

Chassis > ABS/VSC/TRAC/EPB > Clear DTCs

(b) Turn the engine switch off.

(c) Start the engine.

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

(e) Check if the same DTC is output.

Chassis > ABS/VSC/TRAC/EPB > Trouble Codes

Result

Proceed to

C1425 is not output

A

C1425 is output

B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

5.

CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(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 connector.

OK:

The connector is securely connected.

(c) Disconnect the A28 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

A28-42 (STP) - Body ground

Stop light switch assembly on (Brake pedal depressed)

(+BS x 0.85) to 14 V*

A28-42 (STP) - Body ground

Stop light switch assembly off (Brake pedal released)

Below 1.5 V

HINT:

*: The minimum voltage value varies depending on the +BS terminal voltage value. The minimum voltage is 85% or more of the +BS terminal voltage.

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

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