Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Open Circuit in Stop Light Switch Circuit (C1249)

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. DTCs may be stored if either of the following occurs:

• Stop light switch assembly stuck on malfunction.
• The accelerator and brake pedals are depressed simultaneously.*

HINT:

*: The skid control ECU (brake actuator assembly) may store this DTC upon judging that a stuck on malfunction has occurred when the accelerator pedal and brake pedal are depressed simultaneously. However, this does not indicate a malfunction.

WIRING DIAGRAM

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

(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.

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

HINT:

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

NEXT

(a) Interview the customer to check if the pedals were depressed simultaneously while driving or braking.

OK:

The pedals were not depressed simultaneously.

HINT:

The skid control ECU (brake actuator assembly) may store this DTC upon judging that a stuck on malfunction has occurred when the accelerator pedal and brake pedal are depressed simultaneously.

If the pedals were depressed simultaneously, clear the DTC because it is not a malfunction.

NG

GO TO STEP 7

OK

(a) Inspect the stop light switch assembly.

Click here

OK:

The stop light switch assembly is normal.

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

(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.

(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 6

OK

(a) Clear the DTCs.

(b) Turn the engine switch off.

(c) Start the engine.

(d) Drive the vehicle and depress the brake pedal several times to test the stop light circuit.

(e) Check if the same DTC is output.

A

USE SIMULATION METHOD TO CHECK

B

REPLACE 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 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:

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)

(a) Clear the DTCs.

NEXT

END