ECD SYSTEM, Diagnostic DTC:P0504

DTC Code DTC Name
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.

Tech Tips

The normal conditions are as shown in the table below. The signals can be read using the intelligent tester.

Signal Brake Pedal Released In Transition Brake Pedal Depressed
STP OFF ON ON
ST1- ON ON OFF
P0504
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Release and depress brake pedal with ignition switch ON.

  • Conditions (a), (b) and (c) continue for 5.0 seconds or more:


    1. Ignition switch ON

    2. Brake pedal depressed

    3. STP signal off when ST1 signal off

  • (2 trip detection logic)

  • Short in stop light switch signal circuit

  • Stop light switch

  • ECM
Related Data List
DTC No. Data List
P0504

  • Stop Light Switch

WIRING DIAGRAM

A0117ZIE01

INSPECTION PROCEDURE

Note


  • When replacing the ECM, the ECM needs Registration and Initialization Click here.

  • Inspect the fuse for circuits related to this system before performing the following inspection procedure.

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.

  • Stop light switch conditions can be checked using the intelligent tester.


    1. Connect the intelligent tester to the DLC3.

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

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

    4. Check Stop Light Switch when the brake pedal is depressed and released.

      Brake Pedal Operation Specified Condition
      Depressed ON
      Released OFF

PROCEDURE


  1. CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)


    1. A0117K8E07
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Stop Light Switch)

      Disconnect the stop light switch connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A27-2 - Body ground Always 11 to 14 V
      A27-3 - Body ground Ignition switch ON 11 to 14 V

    3. Reconnect the stop light switch connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. A0118EZE01

      Remove the stop light switch.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch pin not pushed Below 1 Ω
      Switch pin pushed 10 kΩ or higher
      3 - 4 Switch pin not pushed 10 kΩ or higher
      Switch pin pushed Below 1 Ω

    3. Reinstall the stop light switch.


    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  3. CHECK ECM (STP AND ST1- VOLTAGE)


    1. A011B8HE02

      Disconnect the ECM connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Brake Pedal Condition Specified Condition
      A19-28 (ST1-) - Body ground Released 11 to 14 V
      Depressed 0 to 3 V
      A19-29 (STP) - Body ground Released 0 to 3 V
      Depressed 11 to 14 V

    4. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  4. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  5. REPLACE STOP LIGHT SWITCH ASSEMBLY


    1. Replace the stop light switch assembly Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

  7. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch to ON.

    4. Depress the brake pedal for 10 seconds or more.

    5. Confirm that the DTC is not output again.


    NEXT

    END