ECD SYSTEM, Diagnostic DTC:P0504

DTC Code DTC Name
P0504 Brake Switch "A" / "B" Correlation

DESCRIPTION

In this system, signals of the stop light switch assembly are used to judge whether the brake system is abnormal or not.

The stop light switch assembly has a duplex system (signals STP and ST1-) to memorize the abnormality when the signals indicating that the brake pedal is depressed and released are detected simultaneously.

Tech Tips

Normal condition is as shown in the table below.

Signal Brake Pedal Released In Transition Brake Pedal Depressed
STP OFF ON ON
ST1- ON ON OFF
DTC No. DTC Detection Condition Trouble Area
P0504

Conditions (a) and (b) continue for 0.5 seconds or more:

(a) Ignition switch ON

(b) Open or short in stop light switch signal circuit

  • Short in stop light switch signal circuit

  • Stop light switch assembly

  • ECM

WIRING DIAGRAM

A01CGV7E01

INSPECTION PROCEDURE

Note

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

Tech Tips


  • Read freeze frame data using the intelligent tester. 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 moving or stationary, whether the engine was warmed up or not, as well as other data recorded at the time of a malfunction.

  • STP signal conditions can be checked using the intelligent tester.


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the tester on.

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

    6. Check the STP signal when the brake pedal is depressed and released.

      Result
      Brake Pedal Operation Specified Condition
      Depressed ON (STP signal ON)
      Released OFF (STP signal OFF)

PROCEDURE


  1. CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL VOLTAGE)


    1. A01CI2LE08
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly 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 Switch Condition Specified Condition
      S15-4 - Body ground Ignition switch ON 18 to 27 V

    4. Reconnect the stop light switch assembly connector.


    NG

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IGNITION SWITCH ASSEMBLY) Click here

    OK

  2. CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL VOLTAGE)


    1. A01CI2LE08
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      S15-2 - Body ground Always 18 to 27 V

    3. Reconnect the stop light switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)

    OK

  3. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. A01CJ4ME04
      Text in Illustration
      *1

      Component without harness connected

      (Stop Light Switch Assembly)

      Remove the stop light switch assembly.

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

      Standard Resistance
      Tester Connection 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 assembly.


    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    OK

  4. CHECK ECM (STP AND ST1- VOLTAGE)


    1. A01CH6GE04
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to ECM)

      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 Condition Specified Condition
      E25-8 (ST1-) - Body ground Depressed Below 2 V
      Released 18 to 27 V
      E25-18 (STP) - Body ground Depressed 18 to 27 V
      Released Below 2 V

    4. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)

    OK

    REPLACE ECM Click here

  5. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IGNITION SWITCH ASSEMBLY)


    1. Disconnect the stop light switch assembly connector.

    2. Disconnect the ignition switch assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      S15-4 - I6-10 (IG1) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      S15-4 or I6-10 (IG1) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. Reconnect the ignition switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IGNITION SWITCH ASSEMBLY)

    OK

  6. INSPECT IGNITION SWITCH ASSEMBLY


    1. A01CHNME15
      Text in Illustration
      *1

      Component without harness connected

      (Ignition Switch Assembly)

      Disconnect the ignition switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      All terminal LOCK 10 kΩ or higher
      9 (AM1) - 10 (IG1) ON Below 1 Ω

    3. Reconnect the ignition switch assembly connector.


    NG

    REPLACE IGNITION SWITCH ASSEMBLY

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY)