CHECK ECM (STP AND ST1- VOLTAGE)
CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)
CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)
REPLACE STOP LIGHT SWITCH ASSEMBLY
CHECK WHETHER DTC OUTPUT RECURS
REPAIR OR REPLACE HARNESS OR CONNECTOR
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
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 that 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.
| Signals | Brake Pedal Released | In Transition | Brake Pedal Depressed |
| STP | OFF | ON | ON |
| ST1- | ON | ON | OFF |
| DTC Detection Drive Pattern | DTC Detection Condition | Trouble Area |
| Depress and release brake pedal with ignition switch ON | Conditions (a), (b) and (c) continue for 0.5 seconds or more (1 trip detection logic): (a) Ignition switch is ON. (b) Brake pedal is released. (c) The STP signal is off when the ST1- signal is off, or the STP signal is on when the ST1- signal is on. |
|
| DTC No. | Data List |
| P0504 | Stop Light Switch |
WIRING DIAGRAM
INSPECTION PROCEDURE
- HINT:
- Read freeze frame data using the intelligent tester. 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, and other data from the time the malfunction occurred.
- Stop light switch conditions can be checked using the intelligent tester.
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to ON.
- Turn the tester on.
- Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.
- Check Stop Light Switch when the brake pedal is depressed and released.
| Brake Pedal Operation | Specified Condition |
| Depressed | ON |
| Released | OFF |
- NOTICE:
- Inspect the fuses of circuits related to this system before performing the following inspection procedure.
- After replacing the ECM, the new ECM needs registration (LandCruiser RM0000012XK0ARX.html) and initialization (LandCruiser RM000000TIN08CX.html).
| 1.CHECK ECM (STP AND ST1- VOLTAGE) |
 |
Disconnect the ECM connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Brake Pedal Condition Specified Condition G57-9 (ST1-) - Body ground Released 11 to 14 V Depressed 0 to 3 V G57-8 (STP) - Body ground Released 0 to 3 V Depressed 11 to 14 V
Text in Illustration *a Brake pedal depressed *b Brake pedal released *c Component with harness connected
(ECM)
Reconnect the ECM connector.
|
| ||||
|
| ||||
| 2.CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE) |
Disconnect the stop light switch connector.
 |
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 Ignition switch ON 11 to 14 V
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
Text in Illustration *a Front view of wire harness connector
(to Stop Light Switch)
Reconnect the stop light switch assembly connector.
|
| ||||
| OK | |
| 3.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM) |
Disconnect the stop light switch assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
Tester Connection Condition Specified Condition A85-2 (L) - G57-8 (STP) Always Below 1 Ω A85-4 (L) - G57-9 (ST1-) Always Below 1 Ω
- Standard Resistance (Check for Short):
Tester Connection Condition Specified Condition A85-2 (L) or G57-8 (STP) - Body ground Always 10 kΩ or higher A85-4 (L) or G57-9 (ST1-) - Body ground Always 10 kΩ or higher
Reconnect the stop light switch assembly connector.
Reconnect the ECM connector.
|
| ||||
| OK | |
| 4.REPLACE STOP LIGHT SWITCH ASSEMBLY |
Replace the stop light switch assembly (LandCruiser RM000003QJT01GX.html).
| NEXT | |
| 5.CHECK WHETHER DTC OUTPUT RECURS |
Connect the intelligent tester to the DLC3.
Clear the DTCs (LandCruiser RM000000PDK1DJX.html).
Turn the ignition switch off.
Turn the ignition switch to ON and turn the tester on.
Depress and release the brake pedal.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Confirm that the DTC is not output again.
- OK:
- DTC is not output again.
|
| ||||
| OK | ||
| ||
| 6.REPAIR OR REPLACE HARNESS OR CONNECTOR |
Repair or replace the harness or connector.
|
| ||||
| 7.REPLACE ECM |
Replace the ECM (LandCruiser RM0000013Z002CX.html).
| NEXT | |
| 8.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
Connect the intelligent tester to the DLC3.
Clear the DTCs (LandCruiser RM000000PDK1DJX.html).
Turn the ignition switch off.
Turn the ignition switch to ON and turn the tester on.
Depress and release the brake pedal.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Confirm that the DTC is not output again.
| NEXT | ||
| ||