CRUISE CONTROL CRUISE CONTROL SYSTEM P0571 Brake Switch "A" Circuit

DESCRIPTION

When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. When the ECM receives this signal, it cancels control of vehicle speed by the cruise control system. 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 applied to terminal STP of the ECM through the STOP fuse and the stop light switch assembly, and the ECM cancels control of vehicle speed by the cruise control system.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
P0571	Brake Switch "A" Circuit	When voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 sec. or more.	· Stop light switch assembly · Stop light switch circuit · ECM

WIRING DIAGRAM

0.271,0.917 1.219,1.281 0.948,0.365 10 false from IGN Fuse 0.156,0.396 1.24,0.771 1.083,0.375 10 false from STOP Fuse 3.177,0.823 3.333,1.021 0.156,0.198 10 false 5 4.104,0.438 4.26,0.635 0.156,0.198 10 false 2 3.188,0.323 3.344,0.521 0.156,0.198 10 false 1 4.115,1 4.271,1.198 0.156,0.198 10 false 4 3.177,1.167 3.333,1.365 0.156,0.198 10 false 3 2.521,1.646 2.833,1.844 0.313,0.198 10 false A1 2.792,1.656 4.688,2.063 1.896,0.406 10 false Stop Light Switch Assembly 5.646,1.646 5.969,1.854 0.323,0.208 10 false A40 6.021,1.646 6.417,1.917 0.396,0.271 10 false ECM 5.615,0.979 5.844,1.198 0.229,0.219 10 false 10 5.667,0.448 5.823,0.646 0.156,0.198 10 false 9 5.844,1.104 6.24,1.313 0.396,0.208 10 false ST1- 5.844,0.531 6.24,0.74 0.396,0.208 10 false STP 3.323,1.281 3.781,1.479 0.458,0.198 10 false GND 3.323,0.927 3.531,1.146 0.208,0.219 10 false B 3.927,0.531 4.271,0.74 0.344,0.208 10 false L 3.927,1.083 4.083,1.281 0.156,0.198 10 false L 3.323,0.438 3.479,0.635 0.156,0.198 10 false B

CAUTION / NOTICE / HINT

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

PROCEDURE

1.CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)

1.469,0.188 1.865,0.438 0.396,0.25 0.729,1.24 1.292,1.24 true 2.125,1.24 2.688,1.24 true 1.583,0.219 1.802,0.427 0.219,0.208 10 false A1 0.583,1.156 0.74,1.354 0.156,0.198 10 false B 2.729,1.156 2.885,1.354 0.156,0.198 10 false B 0.094,0.083 0.302,0.313 0.208,0.229 10 false *a

*a	Front view of wire harness connector (to Stop Light Switch Assembly)

Disconnect the A1 stop light switch assembly connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A1-1 (B) - Body ground	Always	11 to 14 V
A1-5 (B) - Body ground	Ignition switch ON	11 to 14 V

Result:

Proceed to
OK
NG

2.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)

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

2.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)

Disconnect the A1 stop light switch assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A1-3 (GND) - Body ground	Always	Below 1 Ω

Result:

Proceed to
OK
NG

3.CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)

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

3.CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)

Disconnect the A40 ECM connector.

Disconnect the A1 stop light switch assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A40-9 (STP) - A1-2 (L)	Always	Below 1 Ω
A40-10 (ST1-) - A1-4 (L)	Always	Below 1 Ω
A40-9 (STP) or A1-2 (L) - Body ground	Always	10 kΩ or higher
A40-10 (ST1-) or A1-4 (L) - Body ground	Always	10 kΩ or higher

Result:

Proceed to
OK
NG

4.REPLACE STOP LIGHT SWITCH ASSEMBLY

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

4.REPLACE STOP LIGHT SWITCH ASSEMBLY

Replace the stop light switch assembly.

Click hereVehicle Exterior>LIGHTING (EXT)>STOP LIGHT SWITCH>REMOVAL

Result:

Proceed to
NEXT

5.CHECK FOR DTCs (CRUISE CONTROL SYSTEM)

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs.

Click hereEngine / Hybrid System>CRUISE CONTROL>CRUISE CONTROL SYSTEM>DTC CHECK / CLEAR

Powertrain > Cruise Control > Clear DTCs: 50002 237

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.

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

Check for DTCs.

Click hereEngine / Hybrid System>CRUISE CONTROL>CRUISE CONTROL SYSTEM>DTC CHECK / CLEAR

Powertrain > Cruise Control > Trouble Codes: 50001 237

Result:

Result	Proceed to
DTCs are not output	A
DTC P0571 is output	B

END (STOP LIGHT SWITCH ASSEMBLY WAS DEFECTIVE)

REPLACE ECM

Click hereEngine / Hybrid System>2ZR-FE ENGINE CONTROL>ECM>REMOVAL