Dtc P0504 Brake Switch A / B Correlation

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING GTS (STOP LIGHT SWITCH)

INSPECT STOP LIGHT SWITCH ASSEMBLY (B+ VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

INSPECT 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) continue for 0.5 seconds or more
(1 trip detection logic):
(a) Engine switch is on (IG).
(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. 1UR-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.
STP signal conditions can be checked using the GTS.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / All Data / Stop Light Switch.
Check the STP signal when the brake pedal is depressed and released.
Brake Pedal OperationSpecified Condition
DepressedSTP signal ON
ReleasedSTP signal OFF
1.READ VALUE USING GTS (STOP LIGHT SWITCH)

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

Enter the following menus: Powertrain / Engine and ECT / All Data / Stop Light Switch.

Read the value displayed on the GTS.

  • Standard:
  • ConditionSpecified Condition
    Brake pedal depressedSTP signal ON
    Brake pedal releasedSTP signal OFF
NG
Go to step 2
OK
CHECK FOR INTERMITTENT PROBLEMS ()
2.INSPECT STOP LIGHT SWITCH ASSEMBLY (B+ VOLTAGE)
Dtc P0504 Brake Switch A / B Correlation. 1UR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the stop light switch 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 groundEngine switch on (IG)11 to 14 V
Text in Illustration
*aFront view of wire harness connector
(to Stop Light Switch)
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STOP LIGHT SWITCH)
OK
3.INSPECT STOP LIGHT SWITCH ASSEMBLY

Inspect the stop light switch assembly ().

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

Disconnect the ECM connector.

Turn the engine switch on (IG).

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

  • Standard Voltage:
  • for RHD
    Tester ConnectionConditionSpecified Condition
    A52-35 (ST1-) - Body groundBrake pedal released7.5 to 14 V
    Brake pedal depressedBelow 1.5 V
    A52-36 (STP) - Body groundBrake pedal releasedBelow 1.5 V
    Brake pedal depressed7.5 to 14 V
  • for LHD
    Tester ConnectionConditionSpecified Condition
    A38-35 (ST1-) - Body groundBrake pedal released7.5 to 14 V
    Brake pedal depressedBelow 1.5 V
    A38-36 (STP) - Body groundBrake pedal releasedBelow 1.5 V
    Brake pedal depressed7.5 to 14 V
Text in Illustration
*Afor RHD
*Bfor LHD
*aDepressed
*bReleased
*cComponent with harness connected
(ECM)
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM ()