P0504

2AR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0504: Brake Switch "A" / "B" Correlation
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 conditions are as shown in the table below. The signals can be read using the Techstream.









CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) [A].

4. Depress and release the brake pedal [B].

5. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

6. Input the DTC: P0504.

7. Check the DTC judgment result[C].





HINT
If the judgment result shows ABNORMAL, the system has a malfunction.

8. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine and ECT / Trouble Code / Pending.

9. Read Pending DTCs.

HINT
If a pending DTC is output, the system is malfunctioning.

10. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
- Read freeze frame data using the Techstream. 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 Techstream.
(1) Connect the Techstream to the DLC3.
(2) Turn the ignition switch to ON.
(3) Turn the Techstream on.
(4) Enter the following menus: Powertrain / Engine and ECT / All Data / Stop Light Switch.
(5) Check the STP signal when the brake pedal is depressed and released.





NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. INSPECT STOP LIGHT SWITCH (TERMINAL VOLTAGE)





(a) Disconnect the stop light switch connector.

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

Standard Voltage:





(c) Reconnect the stop light switch connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STOP LIGHT SWITCH)
OK -- Continue to next step.

2. INSPECT STOP LIGHT SWITCH

(a) Inspect the stop light switch Testing and Inspection.

NG -- REPLACE STOP LIGHT SWITCH Removal
OK -- Continue to next step.

3. INSPECT ECM (STP AND ST1- VOLTAGE)





(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:





(d) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal