Up to 08/2009

CRUISE CONTROL: DYNAMIC RADAR CRUISE CONTROL SYSTEM: P0571: Brake Switch "A" Circuit
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 fuse and the stop light switch, and the ECM turns the cruise control off.

- The ECM receives the brake demand signal from the driving support ECU and transmits it to the skid control ECU. The skid control ECU receives a signal from the ECM and operates the brake actuator. The skid control ECU operates the brake actuator and at the same time illuminates the stop light by operating the stop light control relay.





WIRING DIAGRAM





INSPECTION PROCEDURE

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

PROCEDURE

1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Radar Cruise / Data List.

(e) Check the Data List for proper functioning of the stop light switch.

Radar Cruise





OK:

Display changes according to brake pedal operation described in above table.

NG -- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE CIRCUIT)
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP FUSE)

(a) Disconnect the stop light control relay.





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

Standard Voltage:





(c) Reconnect the stop light control relay.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - STOP FUSE)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BODY GROUND)

(a) Disconnect the stop light control relay.





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

Standard Resistance:





(c) Reconnect the stop light control relay.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - BODY GROUND)
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH ASSEMBLY)

(a) Disconnect the stop light control relay connector.





(b) Disconnect the stop light switch assembly connector.

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

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the stop light switch assembly connector.

(e) Reconnect the stop light control relay connector.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH ASSEMBLY)
OK -- Continue to next step.

5. INSPECT STOP LIGHT CONTROL RELAY

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





Standard Voltage:





Text in Illustration





NG -- REPLACE STOP LIGHT CONTROL RELAY
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - SKID CONTROL ECU)

(a) Disconnect the stop light switch assembly connector.





(b) Disconnect the skid control ECU connector.

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

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the stop light switch assembly connector.

(e) Reconnect the skid control ECU connector.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - SKID CONTROL ECU)
OK -- Continue to next step.

7. CHECK DTC OUTPUT

(a) Clear the DTCs Dynamic Radar Cruise Control System.

(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) Drive the vehicle at a speed of 50 km/h (31 mph) or more.

(2) Turn the cruise control main switch on.

(3) Push the -SET switch to activate the cruise control.

(c) Check for DTCs Dynamic Radar Cruise Control System.

Result:





B -- REPLACE BRAKE ACTUATOR Components

A -- END

8. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE CIRCUIT)

(a) Disconnect the stop light switch assembly connector.

Text in Illustration









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

Standard Voltage:





(c) Reconnect the stop light switch assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECU IG2 FUSE, STOP FUSE)
OK -- Continue to next step.

9. INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Remove the stop light switch assembly Removal.





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

Standard Resistance:





(c) Install the stop light switch assembly Installation.

NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
OK -- Continue to next step.

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

(a) Disconnect the ECM connector.

Text in Illustration









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

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

Standard Voltage:





(d) Reconnect the ECM connector.

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

OK -- REPLACE ECM Components