Stop Lamp Switch: 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 cancellation trouble, EPB function cancellation trouble, Stop lamp lighting trouble, ESP OFF light illuminated.	(1) A waveform inspection is performed using an oscilloscope on each part during vehicle acceleration/braking. (Refer to INSPECT THE STOP LAMP CIRCUIT Procedures) (2) 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 cancellation trouble, EPB function cancellation 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 cancellation trouble, EPB function cancellation 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 cancellation trouble, EPB function cancellation trouble, Stop lamp lighting trouble, ESP OFF light illuminated.
Engine control module (ECM)		DTC Code: P0504 Symptom: Shifting gear trouble, Cruise control function cancellation 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 cancellation trouble, EPB function cancellation trouble
Smart Key Unit (SMK)		Starting failure
Electronic parking brake		Symptom: EPB function cancellation 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	(1) Inspect waveform using an oscilloscope on each part during vehicle acceleration/braking. (Refer to INSPECT THE STOP LAMP CIRCUIT Procedures) (2) 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 not working	Switch fuse, Relay fuse, Stop lamp switch, Stop signal electronic module, Wire/Connector disconnected
Stop lamp always turned on	Stop lamp switch, Stop signal electronic module, Wiring short circuit, Damaged fuse

Refer to DTC INDEX when the related DTC codes are displayed.