Dtc P0504 Brake Switch A / B Correlation


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)

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

CHECK ECM (STP AND ST1 - VOLTAGE)

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

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


DESCRIPTION

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and stores the DTC.

HINT:
The normal switch conditions are as shown in the table below.

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

DTC No.
DTC Detection Condition
Trouble Area
P0504
Conditions (a), (b) and (c) are met for 0.5 seconds or more (1 trip detection logic):
(a) The engine switch is on (IG).
(b) The brake pedal is released.
(c) The STP signal is OFF when the ST1- signal is OFF.
  1. Short in stop light switch signal circuit
  2. STOP fuse
  3. IGN fuse
  4. Stop light switch
  5. ECM

WIRING DIAGRAM

  1. for Automatic Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. for Manual Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0504 Brake Switch A / B Correlation


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
  1. Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
  2. STP signal conditions can be checked using the GTS.
    1. Connect the GTS to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the GTS on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.
    5. Check the STP signal when the brake pedal is depressed and released.

Brake Pedal Operation
Specified Condition
Depressed
STP signal ON
Released
STP signal OFF
1.CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. Disconnect the stop light switch connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A85-1 (B) - Body ground
    		Always
    		11 to 14 V
    A85-5 (B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Stop Light Switch)

  1. Reconnect the stop light switch connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Disconnect the stop light switch assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A85-3 (GND) - Body ground
    		Always
    		Below 1 Ω

  1. Reconnect the stop light switch assembly connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK ECM (STP AND ST1 - VOLTAGE)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0504 Brake Switch A / B Correlation

  1. Turn the engine switch on (IG).

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

    Standard Voltage:
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    G56-34 (ST1-) - Body ground
    		Brake pedal released
    		11 to 14 V
    Brake pedal depressed
    		0 to 3 V
    G56-35 (STP) - Body ground
    		Brake pedal released
    		0 to 3 V
    Brake pedal depressed
    		11 to 14 V
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    G55-8 (ST1-) - Body ground
    		Brake pedal released
    		11 to 14 V
    Brake pedal depressed
    		0 to 3 V
    G56-18 (STP) - Body ground
    		Brake pedal released
    		0 to 3 V
    Brake pedal depressed
    		11 to 14 V
    Text in Illustration
    *A
    		for Automatic Transmission
    *B
    		for Manual Transmission
    *a
    		Brake Pedal Depressed
    *b
    		Brake Pedal Released
    *c
    		Component with harness connected
    (ECM)


NG
Go to step 4
OK

REPLACE ECM (LandCruiser RM00000329203TX.html)

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

  1. Disconnect the stop light switch assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Open):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    A85-2 (L) - G56-35 (STP)
    		Always
    		Below 1 Ω
    A85-4 (L) - G56-34 (ST1-)
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    A85-2 (L) - G56-18 (STP)
    		Always
    		Below 1 Ω
    A85-4 (L) - G55-8 (ST1-)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    A85-2 (L) or G56-35 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A85-4 (L) or G56-34 (ST1-) - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    A85-2 (L) or G56-18 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A85-4 (L) or G55-8 (ST1-) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE STOP LIGHT SWITCH ASSEMBLY (LandCruiser RM000003QJT01GX.html)