P0504

2GR-FSE 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 2 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 sets the DTC.





CONFIRMATION DRIVING PATTERN





- Connect the Techstream to the DLC3.

- Turn the engine switch on (IG) and turn the Techstream on.

- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) DTC Check / Clear.

- Turn the engine switch off and wait for 30 seconds.

- Turn the engine switch on (IG) and turn the Techstream on [A].

- Depress and release the brake pedal [B].

- Enter the following menus: Powertrain / Engine / Trouble Codes.

- Read the DTC [C].

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Input the DTC: P0504.

- Check the DTC judgment result.





HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform step [B] again.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Check the DTC judgment result.

HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows NORMAL, the system is normal.
- If the test result is INCOMPLETE or UNKNOWN and no 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. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.

PROCEDURE

1. CHECK OPERATION OF STOP LIGHT

(a) Check whether the stop lights turn on and off normally when the brake pedal is depressed and released.

OK:

Stop lights turn on when brake pedal is depressed.

NG -- REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
OK -- Continue to next step.

2. INSPECT STOP LIGHT SWITCH





(a) Remove the stop light switch assembly.

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

Standard resistance:





(c) Reinstall the stop light switch assembly.

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

3. READ VALUE USING TECHSTREAM (STP SIGNAL AND ST1- VOLTAGE)





(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream on.

(c) Select the following menu items: Powertrain / Engine / Data List / Stop Light Switch.

(d) Check the STP signal when the brake pedal is depressed and released.

Standard:





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

Standard voltage:





OK -- CHECK FOR INTERMITTENT PROBLEMS
NG -- Continue to next step.

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

(a) Disconnect the A35 stop light switch connector.

(b) Disconnect the A6 and A7 ECM connectors.

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

Standard resistance (Check for open):





Standard resistance (Check for short):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal