Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VIH9
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 - 08/2016]
Title: CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571; Brake Switch "A" Circuit; 2016 MY Sienna [12/2015 - 08/2016]

DTC

P0571

Brake Switch "A" Circuit

DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. The cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the ECM through the STOP SW fuse and the stop light switch, and the ECM turns the cruise control off.

DTC No.

DTC Detection Condition

Trouble Area

P0571

Voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 seconds or more

  • Stop light switch
  • Stop light switch circuit
  • ECM

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

CONFIRM VEHICLE TYPE

(a) Confirm vehicle type.

Result

Result

Proceed to

for Bulb Type Stop Light

A

for LED Type Stop Light

B

B

GO TO STEP 5

A

2.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - POWER SOURCE)

(a) Disconnect the stop light switch 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

Text in Illustration

*a

Front view of wire harness connector

(to Stop Light Switch)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

INSPECT STOP LIGHT SWITCH

(a) Remove the stop light switch (See page 2016 - 2020 MY Sienna [12/2015 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: REMOVAL ).

(b) Inspect the stop light switch (See page 2016 - 2020 MY Sienna [12/2015 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: INSPECTION ).

NG

REPLACE STOP LIGHT SWITCH

OK

4.

CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)

(a) Disconnect the A39 ECM connector.

(b) Disconnect the A58 stop light switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A39-36 (STP) - A58-1

Always

Below 1 Ω

A39-35 (ST1-) - A58-3

Always

Below 1 Ω

A39-36 (STP) or A58-1 - Body ground

Always

10 kΩ or higher

A39-35 (ST1-) or A58-3 - Body ground

Always

10 kΩ or higher

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - POWER SOURCE)

(a) Disconnect the stop light switch connector.

(b) Measure the voltage and resistance 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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A59-3 (GND) - Body ground

Always

Below 1 Ω

Text in Illustration

*a

Front view of wire harness connector

(to Stop Light Switch)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.

CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)

(a) Disconnect the A39 ECM connector.

(b) Disconnect the A59 stop light switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A39-35 (ST1-) - A59-4 (L)

Always

Below 1 Ω

A39-36 (STP) - A59-2 (L)

Always

Below 1 Ω

A39-35 (ST1-) or A59-4 (L) - Body ground

Always

10 kΩ or higher

A39-36 (STP) or A59-2 (L) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

REPLACE STOP LIGHT SWITCH

(a) Replace the stop light switch (See page 2016 - 2020 MY Sienna [12/2015 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: REMOVAL ).

NEXT

8.

CHECK FOR DTCS (CRUISE CONTROL SYSTEM)

(a) Clear the DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; CRUISE CONTROL: CRUISE CONTROL SYSTEM: DTC CHECK / CLEAR ).

(b) Perform the following to make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the malfunction cannot be detected.

(1) Turn the cruise control system on using the cruise control switch (ON/OFF button).

(c) Check for DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; CRUISE CONTROL: CRUISE CONTROL SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

DTC P0571 is not output

A

DTC P0571 is output

B

A

END (STOP LIGHT SWITCH WAS DEFECTIVE)

B

REPLACE ECM