P0504

2UR-GSE ENGINE CONTROL: SFI SYSTEM: P0504: Brake Switch "A" / "B" Correlation

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 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.
HINT: The normal conditions are as shown in the table below. The signals can be read using the Techstream.









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.

PROCEDURE

1. 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) Enter the following menus: 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:






NG -- INSPECT STOP LIGHT SWITCH (POWER SOURCE)
OK -- CHECK FOR INTERMITTENT PROBLEMS
2. INSPECT STOP LIGHT SWITCH (POWER SOURCE)





(a) Disconnect the stop light switch.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





(c) Reconnect the stop light switch connector.
NG -- INSPECT FUSE (STOP SW AND IGN FUSE)
OK -- Continue to next step.
3. INSPECT STOP LIGHT SWITCH ASSEMBLY





(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 ASSEMBLY
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)





(a) Disconnect the stop light switch connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





(d) Reconnect the stop light switch connector and ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - ECM)
OK -- REPLACE ECM
5. INSPECT FUSE (STOP SW AND IGN FUSE)





(a) Remove the STOP SW fuse and IGN fuse from the cowl side junction block RH.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(c) Reinstall the STOP SW fuse and IGN fuse.
NG -- REPLACE FUSE (STOP SW AND IGN FUSE)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH POWER SOURCE)