Brake Switch

Components and Component Location

Components

1. Brake Pedal Assembly 2. Stop Lamp Switch

3. Brake Pedal Lever Assembly 4. Brake Pedal Pad

Troubleshooting

Troubleshooting

1. 1
   Component Inspection

   Items	Cause	Symptom
   Fuse Switch	Loose fuse connection, blown fuse	DTC: P0504 Symptom: Shift problems, start-up failure, cruise control cancel problem, EPB cancel function problem, stop lamp lighting problem, ESP OFF indicator lamp on.	① Perform the waveform check with an oscilloscope on each part while the vehicle is accelerating/braking. (Refer to Stop Lamp Switch Schematic - Inspection Procedure) ② If an abnormality is found in the signal, refer to the repair procedure for that part (Refer to the applicable part repair procedure and replace it if necessary).
   Fuse Relay	Loose fuse connection, blown fuse	DTC: P0504 Symptom: Shift problems, start-up failure, cruise control cancel problem, EPB cancel function problem, stop lamp lighting problem, ESP OFF indicator lamp on.
   Stop Lamp Switch	Damaged wiring of each component Incorrect connector connection Faulty component	DTC: P0504 Symptom: Gear shifting problems, no start, cruise control malfunction. Problem with cancel function, problem with EPB cancel function, stop lamp malfunction, ESP OFF indicator light stays on.
   Stop Lamp Electronic Module (if applicable)		DTC: P0504, C2130, C2131 Symptom: Gear shifting problems, no start, cruise control malfunction. Problem with cancel function, problem with EPB cancel function, stop lamp malfunction, ESP OFF indicator light stays on.
   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: Gear shifting problems, no start, cruise control malfunction. Problem with cancel function, problem with EPB cancel function.
   Smart Key Unit (SMK)		Starting Failure
   Electronic Parking Brake (EPB)		Symptom: EPB cancel function problem, ESP OFF lamp illuminated.
   ABS/VDC Control Unit (Pressure Sensor)		Symptom: ESP OFF lamp illuminated.

2. 2
   Symptom Diagnostics

   Symptom	Possible Cause
   Starting Problems	Switch Fuse, Relay Fuse, Stop Lamp Switch, Stop Lamp Electronic Module, ABS/VDC Control Module, Each Wire, Connector	① Check the signal waveform with an oscilloscope at each part while the vehicle is driven. Acceleration/deceleration. (Refer to Brake Light Switch Circuit Inspection procedure.) ② Refer to the applicable repair procedure when an abnormality is detected in the signal (refer to the repair procedure for the applicable part and replace it if necessary).
   Gear Shifting Concerns	Switch Fuse, Relay Fuse, Stop Lamp Switch, Stop Lamp Electronic Module, BCM, ECM, Inhibitor Switch, Each Wire, Connector
   ESP OFF indicator light is on	Switch Fuse, Relay Fuse, Stop Lamp Switch, Stop Lamp Electronic Module, ABS/VDC Control Module, Each Wire, Connector
   P0504	Switch Fuse, Relay Fuse, Stop Lamp Switch, Stop Lamp Electronic Module, ECM, Each Wire, Connector
   Stop lamp does not operate	Switch fuse, relay fuse, stop lamp switch, stop lamp electronic module, disconnected wire/connector
   Stop lamp always on	Stop lamp switch, stop lamp electronic module, Wiring short circuit, blown fuse

3. 3
   Stop Lamp Switch System Diagnosis

   

   

   SSEM: Stop Lamp Electronic Module
4. 4
   Refer to the DTC Chart when the applicable DTCs are displayed.

Repair Procedures

Removal

1. 1
   Turn the ignition switch OFF and disconnect the negative (-) battery terminal.
2. 2
   Remove the emergency pad lower panel. (Refer to Body - "Emergency Pad Lower Panel")
3. 3
   Disconnect the stop lamp switch connector (A).

   

4. 4
   Pull the stopper plate (A) as shown.

   

5. 5
   Turn the brake switch 45° counterclockwise and remove it.

   

6. 6
   Inspect the removed brake light switch according to the procedure below.

   1. Confirm proper connection to the terminal part. Check that the connector is securely attached and the connection mark is present.

      

   2. Perform a resistance inspection of the component.

      

      Resistance (Ω)	3-4	1-2
      Plunger depressed (Switch OFF)	Infinity	0
      Plunger released (Switch ON)	0	0

Installation

1. 1
   Hold the brake pedal arm and fully insert the brake switch until the contact part is no longer visible.

   

2. 2
   After installation, rotate the brake switch 45° clockwise, then install the stopper plate by pressing it in.

   

3. 3
   Check the clearance (A) between the brake switch and the bracket.

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

   

4. 4
   Install the brake switch connector (A).

   

Inspection

1. Check Fuses. Install a test fuse on the switch fuse and relay fuse part to check for normal connection.

2. Analyze CAN Data

1. Analyze the KDS data and check whether there is a malfunction in 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 changes in accordance with the brake ON/OFF switch.

      

3. Inspect Connector of Each Part. Check whether each connector is damaged, whether terminals are overheated or incompletely connected. [Engine Room Junction Box]

[ABS/VDC 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]