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 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 sec. or more. |
|
WIRING DIAGRAM

INSPECTION PROCEDURE
1 READ VALUE OF INTELLIGENT TESTER
ECM (Cruise control):

OK: When the brake pedal is operated, the display changes as shown above.
REPLACE ECM
2 CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)

Standard voltage

3 INSPECT STOP LIGHT SWITCH

Standard resistance

4 CHECK ECM

Standard voltage

REPLACE ECM
Vehicle Speed Sensor Malfunction
Input Signal Circuit MalfunctionDisassembly
1. REMOVE AIR REFINER ELEMENT
(a) Release the 2 claw fittings and remove the air filter
sub-assembly.
(b) Remove the air refiner element from the air filter
cover plate.
2. REMOVE COOLING UNIT DAMPER SERVO SUBASSEMBLY
(a) Remove the 3 screws and the cooling unit damper
servo sub-a ...
Circuit opening relay
Inspection
1. INSPECT CIRCUIT OPENING RELAY
Using an ohmmeter, measure the resistance
according to the value(s) in the table below.
Standard resistance
If the result is not as specified, replace the relay. ...
SFR Solenoid Circuit
DESCRIPTION
The solenoid comes on when signals are received from the ECU and controls the
pressure acting on the
wheel cylinders, thus controlling brake force.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 RECONFIRM DTC
HINT:
These codes are detected when a problem is identified in the
...