ECD SYSTEM, Diagnostic DTC:P1520

DTC Code DTC Name
P1520 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 signal conditions are 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. Detection Item DTC Detection Condition Trouble Area MIL Memory
P1520 Stop Light Switch Circuit Malfunction

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) The STP signal is off when the ST1- signal is off.

  • Open or short in stop light switch signal circuit

  • Stop light switch assembly

  • ECM

 - DTC stored

WIRING DIAGRAM

A01SECZE02

CAUTION / NOTICE / HINT

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.

PROCEDURE


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


    1. B0027DMC25
      *a

      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 Condition Specified Condition
      A35-2 - Body ground Always 11 to 14 V
      A35-4 - Body ground Ignition switch ON 11 to 14 V

    3. Reconnect the stop light switch connector.

      Result
      Proceed to
      OK
      NG

    NG

    GO TO STEP 5 Click 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 ASSEMBLY Click here

    OK

  3. CHECK ECM (STP AND ST1- VOLTAGE)


    1. A01SC0JC13
      *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
      G120-10 (ST1-) - Body ground Released 7.5 to 14 V
      Depressed 0 to 1.5 V
      G120-9 (STP) - Body ground Released 0 to 1.5 V
      Depressed 7.5 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  4. REPLACE ECM


    1. Replace the ECM.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 6 Click 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. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs

    3. Turn the ignition switch off.

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

    5. Depress and release the brake pedal.

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

    7. Confirm that the DTC is not output again.


      Powertrain > Engine and ECT > Trouble Codes
      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

    GO TO STEP 6 Click here