Hyundai Ioniq (AE): Brake System / Stop Lamp Switch. Troubleshooting

Hyundai Ioniq (AE) 2017-2022 Service & Repair Manual / Brake System / Brake System / Stop Lamp Switch. Troubleshooting

Troubleshooting
1.
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.
â‘  A waveform inspection is performed using an oscilloscope on each part during vehicle acceleration/braking. (Refer to stop lamp switch circuit inspection procedures)

â‘¡ 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.

2.
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
â‘  Inspect waveform using an oscilloscope on each part during vehicle acceleration/braking. (Refer to stop lamp switch circuit inspection Procedures)

â‘¡ 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.

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