Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000019SRX
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: 2GR-FKS (ENGINE CONTROL): SFI SYSTEM: P05042B; Brake Switch "A"/"B" Signal Cross Coupled; 2018 - 2020 MY Sienna [11/2017 -        ]

DTC

P05042B

Brake Switch "A"/"B" Signal Cross Coupled

DESCRIPTION

The stop light switch assembly is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch assembly and stores this DTC.

HINT:

The normal signal conditions are as shown in the table below.

Signal (ECM Terminal)

Brake Pedal Released

In Transition

Brake Pedal Depressed

STP

OFF

ON

ON

ST1-

ON

ON

OFF

  • [OFF] denotes ground potential.
  • [ON] denotes battery potential (+B).

On the Techstream, Data List item Stop Light SW is ON when the brake pedal is depressed.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P05042B

Brake Switch "A"/"B" Signal Cross Coupled

Conditions (a) and (b) are met for 0.5 seconds or more (1 trip detection logic):

(a) Ignition switch ON

(b) STP signal OFF when ST1- signal OFF

  • Open or short in stop light switch signal circuit
  • Stop light switch assembly
  • ECM

Does not come on

DTC stored

  • SAE Code: P0504
  • DTC for Mexico Models: Applies

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

  • Stop light switch assembly conditions can be checked using the Techstream.
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Stop Light SW.
    5. Check the Data List indication when the brake pedal is depressed and released.

      Brake Pedal Operation

      Stop Light SW

      Depressed

      ON

      Released

      OFF

  • Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK SPECIFICATIONS

(a) Check the vehicle specifications.

Result

Proceed to

for Bulb Type Stop Light

A

for LED Type Stop Light

B

B

GO TO STEP 5

A

2.

CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL VOLTAGE)

*a

Front view of wire harness connector

(to Stop Light Switch Assembly)

(a) Disconnect the stop light switch assembly connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A58-2 - Body ground

Always

11 to 14 V

A58-4 - Body ground

Ignition switch ON

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)

OK

3.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly (for Bulb Type Stop Light).

Click here 2016 - 2020 MY Sienna [12/2015 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: INSPECTION

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

4.

CHECK ECM (STP AND ST1 - VOLTAGE)

(a) Disconnect the ECM connector.

*a

Brake Pedal Depressed

*b

Brake Pedal Released

*c

Front view of wire harness connector

(to ECM)

-

-

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Brake Pedal Operation

Specified Condition

A69-42 (ST1-) - Body ground

Released

7.5 to 14 V

Depressed

0 to 1.5 V

A69-27 (STP) - Body ground

Released

0 to 1.5 V

Depressed

7.5 to 14 V

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)

5.

CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL VOLTAGE)

*a

Front view of wire harness connector

(to Stop Light Switch Assembly)

(a) Disconnect the stop light switch assembly connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A59-1 (B) - Body ground

Always

11 to 14 V

A59-5 (B) - Body ground

Ignition switch ON

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)

OK

6.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly (for LED Type Stop Light).

Click here 2016 - 2020 MY Sienna [12/2015 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: INSPECTION

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

7.

CHECK ECM (STP AND ST1 - VOLTAGE)

(a) Disconnect the ECM connector.

*a

Brake Pedal Depressed

*b

Brake Pedal Released

*c

Front view of wire harness connector

(to ECM)

-

-

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Brake Pedal Operation

Specified Condition

A69-42 (ST1-) - Body ground

Released

7.5 to 14 V

Depressed

0 to 1.5 V

A69-27 (STP) - Body ground

Released

0 to 1.5 V

Depressed

7.5 to 14 V

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)