Dtc P0504 Brake Switch A / B Correlation

Engine. Lexus Gs430, Gs300. Uzs190 Grs190
3Uz-Fe Engine Control System. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT SWITCH

INSPECT STOP LIGHT SWITCH

READ DATA LIST

CHECK WIRE HARNESS (STOP LIGHT SWITCH - ECM)

DTC P0504 Brake Switch "A" / "B" Correlation

DTC P0571 Brake Switch "A" Circuit


DESCRIPTION

In addition to turning on the stop lights, the stop light switch signals are used for a variety of engine, transmission and suspension functions. The stop light switch is designed with 2 complementary signal outputs, STP and ST1-. The ECM analyzes these signal outputs to detect malfunctions in the stop light switch.

DTC No.
DTC Detection Condition
Trouble Area
P0504
  1. Conditions (a), (b) and (c) continue for 0.5 sec. or more:
    1. (a) Engine switch on (IG)
    2. (b) Brake pedal released
    3. (c) STP signal is OFF when the ST1- signal is OFF
  1. Short in stop light switch signal circuit
  2. Stop light fuse
  3. Stop light switch
  4. ECM
HINT:
Normal condition is as shown in the table below. The signals can be read using the intelligent tester.

Signal
Brake Pedal Released
In Transition
Brake Pedal Depressed
STP
OFF
ON
ON
ST1-
ON
ON
OFF

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System. Dtc P0504 Brake Switch A / B Correlation


INSPECTION PROCEDURE

1.CHECK STOP LIGHT SWITCH

  1. Check if the stop lights turn on and off normally when the brake pedal is depressed and released.



NG
REPAIR OR REPLACE STOP LIGHT SWITCH
OK


2.INSPECT STOP LIGHT SWITCH
Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. Disconnect the A37 stop light switch.

  1. Measure the resistance of the switch.

    Standard resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Switch pin not pushed
    		Below 1 Ω
    3 - 4
    		Switch pin not pushed
    		10 kΩ or higher
    1 - 2
    		Switch pin pushed in
    		10 kΩ or higher
    3 - 4
    		Switch pin pushed in
    		Below 1 Ω


NG
REPLACE STOP LIGHT SWITCH
OK


3.READ DATA LIST
Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Enter the following menus: Powertrain / Engine / Data List / Primary / Stop Light Switch.

  1. Confirm the stop light switch status when the brake pedal is depressed and released.

    OK:
    Brake Pedal Condition
    		Specified Condition
    Depressed
    		STP Signal ON
    Released
    		STP Signal OFF

  1. Measure the voltage of the ECM when the brake pedal is depressed and released.

    Standard voltage:
    Tester Connection
    		Brake Pedal Condition
    		Specified Condition
    A6-8 (ST1-) - E7-7 (E1)
    		Depressed
    		Below 1.5 V
    A6-8 (ST1-) - E7-7 (E1)
    		Released
    		7.5 to 14 V


OK
CHECK FOR INTERMITTENT PROBLEMS
NG


4.CHECK WIRE HARNESS (STOP LIGHT SWITCH - ECM)
Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. Disconnect the A37 stop light switch connector.

  1. Disconnect the A6 and A7 ECM connectors.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A37-1 - A7-4 (STP)
    		Below 1 Ω
    A37-4 - A6-8 (ST1-)
    		Below 1 Ω
    A37-1 or A7-4 (STP) - Body ground
    		10 kΩ or higher
    A37-4 or A6-8 (ST1-) - Body ground
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM