СИСТЕМА SFI, Diagnostic DTC:P0504

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

DESCRIPTION

In this system, the signal of the stop light switch is used to judge whether the acceleration system is abnormal or not.

The stop light switch has a duplex system (signals STP and ST1-) to memorize the abnormality when the signals of depressing and releasing the brake pedal are detected simultaneously.

Tech Tips

The Normal condition is 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), (b) and (c) continue for 0.5 sec or more:


    • (a) Ignition switch ON

    • (b) Brake pedal released

    • (c) STP signal is OFF when ST1- signal is OFF

  • Short in stop light switch signal circuit

  • STOP fuse

  • Stop light switch

  • ECM

WIRING DIAGRAM

A01DVD5E02

INSPECTION PROCEDURE

Tech Tips

Reed freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK OPERATION OF STOP LIGHT


    1. Check if the stop lights illuminate and turn off normally when the brake pedal is depressed and released.

      OK
      Stop lights illuminate and turn off.

    NG

    REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT

    OK

  2. INSPECT STOP LIGHT SWITCH

    A01DXWSE11

    1. Measure the resistance of the switch.

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

    NG

    REPLACE STOP LIGHT SWITCH

    OK

  3. READ DATA LIST (STP SIGNAL AND ST1 - VOLTAGE)

    A01E0SVE01

    1. Connect the intelligent tester to the DLC3.

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

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

    4. Check the result.

      Standard
      Brake Pedal Specified Condition
      Depressed STP Signal ON
      Released STP Signal OFF

    5. Measure the voltage of the E14 and E17 ECM connectors.

      Standard voltage
      Tester Connection Brake Pedal Specified Condition
      E14-16 (ST1-) - E17-1 (E1) Depressed Below 1.5 V
      E14-16 (ST1-) - E17-1 (E1) Released 7.5 to 14 V

    OK

    CHECK FOR INTERMITTENT PROBLEMS

    NG

  4. CHECK WIRE HARNESS (STOP LIGHT SWITCH - ECM)

    A01DXSFE01

    1. Disconnect the S14 stop light switch connector.

    2. Disconnect the E14 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      S14-1 - E14-15 (STP) Below 1 Ω
      S14-4 - E14-16 (ST1-) Below 1 Ω
      S14-1 or E14-15 (STP) - Body ground 10 kΩ or higher
      S14-4 or E14-16 (ST1-) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE ECM