Hyundai Elantra: Brake System / Stop Lamp Switch Troubleshooting

Hyundai Elantra AD (2016-2020) Service Manual / Brake System / Brake System / Stop Lamp Switch Troubleshooting

Troubleshooting

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.

A waveform inspection is performed using an oscilloscope on each part during vehicle acceleration/braking. (Refer to stop lamp switch circuit inspection procedures)

Refer to the relevant repair procedures of the part when something abnormal is discovered in the waveform (Refer to the repair procedures of the relevant part and if necessary replace it)

Relay 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.

Stop lamp switch

•	Damaged wiring of each part

•	Faulty connection to connector

•	Each part is defective

-	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.

Stop signal electronic
module (If it applies)

-	DTC Code : P0504, C2130, C2131

-	Symptom : Shifting gear trouble, Starting failure, Cruise control function cancelation trouble, EPB function cancelation trouble, Stop lamp lighting trouble , ESP OFF light illuminated.

Engine control module(ECM)

-	DTC Code : P0504

-	Symptom :Shifting gear trouble,Cruise control function cancelation trouble

Body control module (BCM)

-	Shifting gear trouble

Shift-lock solenoid

-	Shifting gear trouble

Inhibitor switch

-	Symptom : Shifting gear trouble, Starting failure, Cruise control function cancelation trouble, EPB function cancelation trouble

Smart Key Unit(SMK)

-	Starting failure

Electronic parking brake

-	Symptom : EPB function cancelation trouble , ESP OFF light illuminated.

ABS/VDC control module
(Pressure sensor)

-	Symptom : ESP OFF light illuminated.

Symptom diagnosis

Symptom	Part that could be the cause
Trouble starting	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, ABS/VDC control module, Each wire, Connector	Inspect waveform using an oscilloscope on each part during vehicle acceleration/braking. (Refer to stop lamp switch circuit inspection Procedures) Refer to the relevant repair procedures of the part when something abnormal is discovered in the waveform (Refer to the repair procedures of the relevant part and if necessary replace it)
Trouble shifting gears	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, BCM, ECM, Inhibitor switch, Each wire, Connector
ESP OFF light illuminated	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, ABS/VDC control module, Each wire, Connector
P0504	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, ECM, Each wire, Connector
Stop lamp does notworking	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, Wire/Connector disconnected
Stop lamp always turns on	Stop lamp switch, Stop signal electronic module, Wiring short circuit, Damaged fuse

3.	Stop lamp switch system diagnosis SSEM : Stop Signal Electronic Module

4.	Refer to DTC guide when the related DTC codes are displayed.

Stop Lamp Switch Schematic Diagrams

Schematic Diagram System circuit diagram Terminal function TeminalDescription1IGN12Engine Control Module (ECM)3B+4Stop Lmap ...

Stop Lamp Switch Repair procedures

Adjustment 1. Turn ignition switch OFF and disconnect the negative (-) battery cable. 2. Remove the lower crash pad. (Refer to Body - "Crash Pad") 3. Confirm the gap between stop lamp swi ...

Other information:

Hyundai Elantra AD (2016-2020) Service Manual: Mode Control Actuator Components and Components Location
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Hyundai Elantra AD (2016-2020) Service Manual: Smart Cruise Control Switch Repair procedures
Inspection [Measuring Resistance] 1. Disconnect the cruise control switch connector from the control switch. 2. Measure resistance between terminals on the control switch when each function switch is ON (switch is depressed). Function switchTerminalResistanceSET -2 - 5550?±5%RES +2 - ...