Brake Switch "A" Circuit

CRUISE CONTROL: DYNAMIC LASER CRUISE CONTROL SYSTEM: P0571: Brake Switch "A" Circuit

DTC P0571 - Brake Switch "A" Circuit

DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the hybrid vehicle control ECU. When the hybrid vehicle control ECU 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 hybrid vehicle control ECU through the STOP SW fuse and the stop light switch, and the hybrid vehicle control ECU turns the cruise control off.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT STOP LIGHT SWITCH
(a) Disconnect the stop light switch connector.





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






NG -- REPLACE STOP LIGHT SWITCH
OK -- Continue to next step.
2. CHECK WIRE HARNESS (STOP LIGHT SWITCH - BATTERY)





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. CHECK HYBRID VEHICLE CONTROL ECU
(a) Reconnect the stop light switch connector.
(b) Disconnect the H29 connector from the hybrid vehicle control ECU.
(c) Turn the ignition switch to the ON position.





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE HYBRID VEHICLE CONTROL ECU