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

B003RSXE02

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 HARNESS AND CONNECTOR (TERMINAL VOLTAGE)


    1. B003N0DC09
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly connector.

    2. Turn the igntion switch to ON

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A64-6 (B) - Body ground Ignition switch ON 11 to 14 V
      A64-7 (B) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY,INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    OK

  2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)


    1. Disconnect the stop light switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A64-2 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ECM (STP AND ST1- VOLTAGE)


    1. B003NYMC11
      *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
      G160-10 (ST1-) - Body ground Released 7.5 to 14 V
      Depressed 0 to 1.5 V
      G160-9 (STP) - Body ground Released 0 to 1.5 V
      Depressed 7.5 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

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


    1. Disconnect the stop light switch assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A64-3 (L) - G160-9 (STP) Always Below 1 Ω
      A64-5 (L) - G160-10 (ST1-) Always Below 1 Ω
      A64-3 (L) or G160-9 (STP) - Body ground and other terminals Always 10 kΩ or higher
      A64-5 (L) or G160-10(ST1-) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR