ECD SYSTEM, Diagnostic DTC:51

DTC Code DTC Name
51 Stop Light Switch Circuit Malfunction

DESCRIPTION

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

The stop light switch has a duplex system (signals STP and ST1-) to recognize 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
51

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

(a) Ignition switch is ON.

(b) Brake pedal is released.

(c) STP signal is off when ST1- signal is off.

  • Open or short in stop light switch signal circuit

  • Stop light switch

  • ECM

WIRING DIAGRAM

A00O8JYE01

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. 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.

When using intelligent tester:

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

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

      OK
      Brake Pedal Display
      Depressed Stop Light SW ON
      Released Stop Light SW OFF

    NG

    CHECK ECM (STP, ST1- VOLTAGE) Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  2. CHECK ECM (STP, ST1- VOLTAGE)


    1. A00O47JE06
      Text in Illustration
      *a Brake pedal depressed
      *b Brake pedal released
      *c

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Brake Pedal Condition Specified Condition
      G61-19 (STP) - C101-14 (E1) Depressed 11 to 14 V
      Released Below 1.5 V
      G62-11 (ST1-) - C101-14 (E1) Depressed Below 1.5 V
      Released 11 to 14 V

    NG

    INSPECT STOP LIGHT SWITCH Click here

    OK

    REPLACE ECM Click here

  3. INSPECT STOP LIGHT SWITCH


    1. Inspect the stop light switch Click here.


    NG

    REPLACE STOP LIGHT SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)


    1. Disconnect the stop light switch connector.

    2. Disconnect the ECM connectors.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A5-1 - G61-19 (STP) Always Below 1 Ω
      A5-3 - G62-11 (ST1-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A5-1 or G61-19 (STP) - Body ground Always 10 kΩ or higher
      A5-3 or G62-11 (ST1-) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPAIR OR REPLACE POWER SOURCE CIRCUIT Click here

When not using intelligent tester:

PROCEDURE


  1. CHECK STOP LIGHT (OPERATION)


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

      OK
      The stop lights go on and off normally.

    NG

    REPAIR STOP LIGHT SWITCH CIRCUIT

    OK

  2. CHECK ECM (STP, ST1- VOLTAGE)


    1. A00O47JE06
      Text in Illustration
      *a Brake pedal depressed
      *b Brake pedal released
      *c

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Brake Pedal Condition Specified Condition
      G61-19 (STP) - C101-14 (E1) Depressed 11 to 14 V
      Released Below 1.5 V
      G62-11 (ST1-) - C101-14 (E1) Depressed Below 1.5 V
      Released 11 to 14 V

    NG

    INSPECT STOP LIGHT SWITCH Click here

    OK

    REPLACE ECM Click here

  3. INSPECT STOP LIGHT SWITCH


    1. Inspect the stop light switch Click here.


    NG

    REPLACE STOP LIGHT SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)


    1. Disconnect the stop light switch connector.

    2. Disconnect the ECM connectors.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A5-1 - G61-19 (STP) Always Below 1 Ω
      A5-3 - G62-11 (ST1-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A5-1 or G61-19 (STP) - Body ground Always 10 kΩ or higher
      A5-3 or G62-11 (ST1-) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPAIR OR REPLACE POWER SOURCE CIRCUIT Click here