Dtc P0504 Brake Switch A / B Correlation

Land Cruiser URJ200 URJ202 GRJ200 VDJ200 - 1GR-FE ENGINE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

CHECK ECM (STP AND ST1- VOLTAGE)

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 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 signal conditions are as shown in the table below.
Signal (ECM Terminal)Brake Pedal ReleasedIn TransitionBrake Pedal Depressed
STPOFFONON
ST1-ONONOFF
[OFF] denotes ground potential.
[ON] denotes battery potential (+B).
On the GTS, the Data List items Stop Light Switch and ST1 are both ON when the brake pedal is depressed because the characteristics of ST1 indication are the opposite of the characteristics of Stop Light Switch indication.
DTC No.DTC Detection ConditionTrouble Area
P0504Conditions (a), (b) and (c) are met for 0.5 seconds or more
(1 trip detection logic):
(a) Ignition switch is ON.
(b) Brake pedal is released.
(c) STP signal is OFF when the ST1- signal is OFF.
Short in stop light switch signal circuit
STOP fuse
IGN fuse
Stop light switch assembly
ECM

WIRING DIAGRAM

Dtc P0504 Brake Switch A / B Correlation. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

INSPECTION PROCEDURE

  • NOTICE:
  • Inspect the fuses of circuits related to this system before performing the following inspection procedure.
  • HINT:
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.
Stop light switch conditions can be checked using the GTS.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Stop Light Switch and ST1.
Check the Data List when the brake pedal is depressed and released.
Brake Pedal OperationStop Light SwitchST1
DepressedONON
ReleasedOFFOFF
1.CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)
Dtc P0504 Brake Switch A / B Correlation. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the stop light switch assembly connector.

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

  • Standard Voltage:
  • Tester ConnectionConditionSpecified Condition
    A30-2 - Body groundAlways11 to 14 V
    A30-4 - Body groundIgnition switch ON11 to 14 V
Text in Illustration
*aFront view of wire harness connector
(to Stop Light Switch Assembly)
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
2.INSPECT STOP LIGHT SWITCH ASSEMBLY

Inspect the stop light switch assembly ().

NG
REPLACE STOP LIGHT SWITCH ASSEMBLY ()
OK
3.CHECK ECM (STP AND ST1- VOLTAGE)
Dtc P0504 Brake Switch A / B Correlation. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the ECM connector.

Turn the ignition switch to ON.

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

  • Standard Voltage:
  • for LHD
    Tester ConnectionBrake Pedal OperationSpecified Condition
    A38-35 (ST1-) - Body groundReleased7.5 to 14 V
    Depressed0 to 1.5 V
    A38-36 (STP) - Body groundReleased0 to 1.5 V
    Depressed7.5 to 14 V
  • for RHD
    Tester ConnectionBrake Pedal OperationSpecified Condition
    A52-35 (ST1-) - Body groundReleased7.5 to 14 V
    Depressed0 to 1.5 V
    A52-36 (STP) - Body groundReleased0 to 1.5 V
    Depressed7.5 to 14 V
Text in Illustration
*Afor LHD
*Bfor RHD
*aBrake Pedal Depressed
*bBrake Pedal Released
*cFront view of wire harness connector
(to ECM)
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM ()