ECD SYSTEM(for DPF), Diagnostic DTC:P0504

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

DESCRIPTION

The stop light switch assembly 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 assembly and stores the DTC.

Tip:

The normal conditions are as shown in the table below.

Signals (ECM Terminal)

Brake Pedal Released

In Transition

Brake Pedal Depressed

STP

OFF

ON

ON

ST1-

ON

ON

OFF

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0504

Brake Switch "A" / "B" Correlation

Conditions (a), (b) and (c) continue for 0.5 seconds or more (1 trip detection logic):

(a) Ignition switch ON.

(b) Brake pedal is released.

(c) The STP signal is off when the ST1- signal is off, or the STP signal is on when the ST1- signal is on.

  • Open or short in stop light switch assembly signal circuit

  • Stop light switch assembly

  • ECM

-

DTC stored
Table 1. Related Data List

DTC No.

Data List

P0504

Stop Light Switch

CONFIRMATION DRIVING PATTERN

DTC No.

DTC Detection Drive Pattern

P0504

Release and depress brake pedal with ignition switch ON

WIRING DIAGRAM

A160611E14

CAUTION / NOTICE / HINT

Note:

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

  • After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).

Tip:

  • Read freeze frame data using the GTS. 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, and other data from the time the malfunction occurred.

  • Stop light switch conditions can be checked using the GTS.

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

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

Brake Pedal Operation

Specified Condition

Depressed

ON

Released

OFF

PROCEDURE

  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)

    1. A148738C06

      *a

      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

      Condition

      Specified Condition

      A5-2 - Body ground

      Always

      11 to 14 V

      A5-4 - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. Inspect the stop light switch assembly.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLYClick here

    OK

  3. CHECK ECM (STP AND ST1- VOLTAGE)

    1. A275087C02

      *a

      Brake Pedal Depressed

      *b

      Brake Pedal Released

      *c

      Front 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

      Brake Pedal Condition

      Switch Condition

      A61-34 (ST1-) - Body ground

      Released

      7.5 to 14 V

      Depressed

      Below 1.5 V

      A61-35 (STP) - Body ground

      Released

      Below 1.5 V

      Depressed

      7.5 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  4. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  5. REPAIR OR REPLACE HARNESS OR CONNECTOR

    1. Repair or replace the harness or connector.

    Result

    Proceed to

    NEXT
    NEXT

  6. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    5. Turn the ignition switch off.

    6. Turn the ignition switch to ON and turn the GTS on.

    7. Release and depress the brake pedal.

    8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    9. Confirm that the DTC is not output again.

    Result

    Proceed to

    NEXT
    NEXT

    END

  7. REPLACE STOP LIGHT SWITCH ASSEMBLY

    1. Replace the stop light switch assembly.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here