Hyundai Ioniq: Brake System / Stop Lamp Switch. Repair procedures

Hyundai Ioniq (AE) 2017-2025 Service Manual / Brake System / Brake System / Stop Lamp Switch. Repair procedures

Removal

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

2.	Remove the lower crash pad. (Refer to Body - "Crash Pad")

3.	Remove the knee airbag. (Refer to Rstraint - "Air Bag Module")

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

5.	Pull the locking plate (A) as indicated by the arrow.

6.	Turn stop lamp switch 45° counterclockwise and remove it.

Inspect a removed stop lamp switch along the below procedures.

(1)

Confirm a normal connection with terminal part

–	A confirmation can be made to see if the connector has been secured properly and if a connection mark is present.

Installation

1.	Fix the brake pedal arm and insert fully the stop lamp switch as hiding contact part. Turn stop lamp switch 45° clockwise and install it.

2.	Assemble locking plate (A) by pushing.

Confirm the gap between stop lamp switch and bracket.

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

•	If the gap between stop lamp switch and bracket is not 1.0 - 2.0 mm (0.04 - 0.08 in), perform the above process again.

4.	Connect the stop lamp switch connector.

5.	Remove the knee airbag. (Refer to Rstraint - "Air Bag Module")

6.	Install the lower crash pad. (Refer to Body - "Crash Pad")

7.	Connect the negative (-) battery cable.

Adjustment

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

2.	Remove the lower crash pad. (Refer to Body - "Crash Pad")

3.	Remove the knee airbag. (Refer to Rstraint - "Air Bag Module")

Confirm the gap between stop lamp switch and bracket.

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

5.	If the gap between stop lamp switch and bracket is not 1.0 - 2.0 mm (0.04 - 0.08 in), check the mounting clip and other part of around stop lamp.

6.	If there is normal, remove the stop lamp switch and then install again.

Inspection

1. Fuse Inspection

Mount the test fuse to the switch fuse and relay fuse part to confirm a normal joint fit.

2. GDS Data Analysis

Analyze GDS data and confirm if there is anything wrong with the stop lamp switch.

(1)	Connect the GDS to the self-diagnosis connector.

(2)	Turn the spark switch on

(3)	Step on the brake pedal.

(4)

Inspect the "brake switch" category that displays the "sensor data" GDS.

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

3. Inspection Of Connector By Each Part

Check to see whether or not each connector has been damaged, or terminal surge, or incomplete connection has taken place

[Engine Room Junction Box]

[ABS / VDC Control Module]

4. Inspect The Stop Lamp Circuit

Connect probe to each terminal wire and confirm oscilloscope waveform.

[Stop Lamp Switch Input / Output]

[Oscilloscope Waveform Screen]

Stop Lamp Switch. Schematic diagrams

S..

Stop Lamp Switch. Troubleshooting

Troubleshooting1. Part diagnosis Items Cause Symptom Switch fuse Faulty fuse connection, Damaged fuse – DTC Code : P0504– Symptom : Shifting gear trouble, Starting failure, Cruise control function cancelation trouble, EPB function cancelation trouble, Stop lamp lighting trouble, ESP OFF light illuminated...

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