Kia Optima DL3 Quiz
Brake System

Stop Lamp Switch

In this manual: Brake System
General Information — 8Advanced Driver Assistance System (ADAS) — 21Maintenance — 27Engine Mechanical System — 45Engine Electrical System — 11Emission Control System — 11Engine Control System/Fuel System — 25Automatic Transmission — 20Drive Shaft and Axle — 7Suspension System — 22Steering — 7Restraints — 11Brake System — 22Body (Interior and Exterior) — 116Body Electrical System — 90Heating, Ventilation, and Air Conditioning — 32
20steps
~120min
4/5difficulty
Done 0 of 20

Components and Component Location

Components

1. Brake Pedal Assembly
2. Stop Lamp Switch
3. Brake Pedal Lever Assembly
4. Brake Pedal Pad

Circuit Diagrams

System Diagram

Schematic Diagram

Terminal Function

Terminal Description
1 IGN1
2 Engine Control Module (ECM)
3 -
4 B+
5 Stop Lamp
6 Ground

Troubleshooting

Troubleshooting

  1. Component Inspection

    Items Cause Symptom
    Fuse Switch Loose fuse connection, blown fuse

    • DTC: P0504

    • Symptom: Shift problems, no start, cruise control cancel function problem, EPB cancel function malfunction, stop lamp malfunction, ESC OFF lamp illuminated.

    		 ① Check the signal waveform using an oscilloscope on each part while the vehicle is accelerating/braking. (Refer to Brake Light Switch Circuit Inspection Procedure)

    ② Refer to the applicable part repair procedure if any abnormality is found in the waveform (refer to the repair procedure for the relevant part and replace if necessary)
    Fuse Relay Loose fuse connection, blown fuse

    • DTC: P0504

    • Symptom: Shift problems, no start, cruise control cancel function problem, EPB cancel function malfunction, stop lamp malfunction, ESC OFF lamp illuminated.
    Stop Lamp Switch

    • Damaged wiring of each component

    • Incorrect connector connection

    • Faulty component

    • DTC: P0504

    • Symptom: Shift problems, no start, cruise control cancel function problem, EPB cancel function malfunction, stop lamp malfunction, ESC OFF lamp illuminated.
    Electronic Brake Light Module (if equipped)

    • DTC: P0504, C2130, C2131

    • Symptom: Shift problems, no start, cruise control cancel function problem, EPB cancel function malfunction, stop lamp malfunction, ESC OFF lamp illuminated.
    Engine Control Module (ECM)

    • DTC: P0504

    • Symptom: Shift problems, cruise control cancel problem
    Body Control Module (BCM)

    • Gear Shifting Concerns
    Shift Lock Solenoid

    • Gear Shifting Concerns
    Inhibitor Switch

    • Symptom: Shift problems, no-start, cruise control cancel problem, EPB release function problem
    Smart Key Unit (SMK)

    • Starting Failure
    Electronic Parking Brake (EPB)

    • Symptom: EPB cancel function problem, ESC OFF lamp illuminated.
    ABS/ESC Control Module
    (Pressure Sensor)

    • Symptom: ESC OFF lamp illuminated.

  2. Symptom Diagnostics

    Symptom Possible Cause
    Starting Problems Switch fuse, relay fuse, stop lamp switch, electronic stop lamp module, ABS/ESC control module, each wire, connector ① Check the signal waveform using an oscilloscope on each part while the vehicle is accelerating/braking. (Refer to Brake Light Switch Circuit Inspection Procedure)

    ② Refer to the applicable part repair procedure if any abnormality is found in the waveform (refer to the repair procedure for the relevant part and replace if necessary)
    Gear Shifting Concerns Switch fuse, relay fuse, brake light switch, electronic brake light module, BCM, ECM, inhibitor switch, each wire, connector
    ESC OFF lamp illuminated Switch fuse, relay fuse, stop lamp switch, electronic stop lamp module, ABS/ESC control module, each wire, connector
    P0504 Switch fuse, relay fuse, brake light switch, electronic brake light module, ECM, each wire, connector
    Stop lamp does not work Switch fuse, relay fuse, brake light switch, electronic brake light module, wire/connector disconnected
    Brake light always ON Brake light switch, electronic brake light module, wiring short circuit, blown fuse

  3. Stop Lamp Switch System Diagnosis

    SSEM: Stop Lamp Electronic Module

  4. Refer to the DTC Chart when the applicable DTCs are displayed.

Repair Procedures

Adjustment

  1. Turn the ignition switch OFF and disconnect the negative (-) battery cable.

  2. Remove the lower cover.

    (Refer to Body — "Emergency Floor")

  3. Check the clearance between the stop lamp switch and the bracket.

    Stop lamp switch clearance (A): 1.0-2.0 mm (0.04-0.08 in.)

  4. If the clearance between the stop lamp switch and the bracket is less than 1.0-2.0 mm (0.04-0.08 in.), check the mounting clip and the surrounding parts of the stop lamp switch.

  5. If everything is normal, remove the stop lamp switch and install it again.

Inspection

1. Check Fuses

Install a test fuse in place of the switch fuse and the relay fuse part to confirm normal operation.

2. Analyze CAN Data

  1. Analyze the KDS data and confirm that there is a problem with the stop lamp switch.

    1. Connect the KDS to the self-diagnosis connector.

    2. Turn the ignition switch ON.

    3. Press the brake pedal.

    4. Check the "Brake Switch" category, which displays the KDS "Sensor Data".

      Normal signal pattern: The brake pressure sensor signal value will change according to the brake switch ON/OFF state.

3. Inspect Connector for Each Part

Check each connector for damage, terminal overtightening, or incomplete connection.

[Engine Room Junction Box]

[ABS/ESC Control Module]

4. Inspect the stop lamp circuit.

Connect the probe to each terminal wire and check the oscilloscope waveform.

[Stop Lamp Switch Input / Output]

[Oscilloscope Waveform Screen]

Removal

  1. Turn the ignition switch OFF and disconnect the negative (-) battery cable.

  2. Remove the lower cover.

    (Refer to Body — "Emergency Floor")

  3. Disconnect the stop lamp switch connector (A).

  4. Pull the lock plate (A) as shown by the arrow.

  5. Turn the brake light switch (A) 45° counterclockwise and remove it.

  6. Inspect the removed stop lamp switch according to the procedures described below.

    1. Confirm normal connection with the terminal part.

      Verify that the connector is properly secured and that the connection mark is present.

Installation

  1. Hold the brake pedal arm and fully insert the brake light switch so that the contact part is hidden.

  2. After inserting, turn the stop switch (A) 45° clockwise, then engage the locking plate by pressing.

  3. Check the clearance between the stop lamp switch and the bracket.

    Stop lamp switch clearance (A): 1.0-2.0 mm (0.04-0.08 in.)

  4. Connect the connector of the brake light switch (A).

  5. Install the lower engine cover.

    (Refer to Body — "Emergency Floor")

Test yourself

A quick Kia Optima DL3 quiz: every answer comes with an explanation and a link to the manual page.