Hyundai Elantra MD/UD: Relay Box (Passenger Compartment). Description and Operation - Fuses And Relays - Body Electrical System - Hyundai Elantra MD 2010-2015 Service manualHyundai Elantra MD/UD: Relay Box (Passenger Compartment). Description and Operation

Description

Smart Junction Box(SJB)
1.
General function : Interior Junction Box + some functions of BCM
It controls loads with CAN communication and IPS.
2.
Main function
A.
Low speed CAN communication(100 kbps)
B.
Self diagnostics(Lamp open/short)
C.
Fail safe(When MCU/CAN is fail, Head lamp / Tail lamp directly drive)
D.
Protection of bulb over-voltage(PWM function)
E.
Cut of Over-load and Short : PCL(Program Current Limit)
Switch control input
No.
Switch input
Value
Destination
Wakeup
1
IG1
ON/OFF
 -
YES
2
IG2
ON/OFF
 -
NO
3
Seat belt switch(Driver)
BELT/UNBELT
BCM
NO
4
Seat belt switch(Passenger)
BELT/UNBELT
BCM
NO
5
Seat belt switch(Rear left)
BELT/UNBELT
BCM
NO
6
Seat belt switch(Rear right)
BELT/UNBELT
BCM
NO
7
Seat belt switch(Rear center)
BELT/UNBELT
BCM
NO
8
Unlock State(Driver door)
LOCK/UNLOCK
BCM,SMK
YES
9
Unlock State(Passenger door)
LOCK/UNLOCK
BCM,SMK
YES
10
Unlock State(Rear left door)
LOCK/UNLOCK
BCM
YES
11
Unlock State(Rear right door)
LOCK/UNLOCK
BCM
YES
12
Driver door switch
CLOSE/OPEN
BCM,CLU,SMK
YES
13
Passenger door switch
CLOSE/OPEN
BCM,CLU,SMK
YES
14
Rear left door switch
CLOSE/OPEN
BCM,CLU,SMK
YES
15
Rear right door switch
CLOSE/OPEN
BCM,CLU,SMK
YES
16
Driver/Passenger door Key lock
OFF/LOCK
BCM
YES
17
Driver door Key unlock
OFF/UNLOCK
BCM
YES
18
Passenger door Key unlock
OFF/UNLOCK
BCM
YES
19
Driver window lock switch
OFF/LOCK
BCM
YES
20
Driver window unlock switch
OFF/UNLOCK
BCM
YES
21
Turn signal switch(Left)
ON/OFF
CLU
NO
22
Turn signal switch(right)
ON/OFF
CLU
NO
23
Hazard switch
ON/OFF
 -
YES
24
Trunk switch
CLOSE/OPEN
BCM,CLU,SMK
YES
25
HID
HID/OFF
 -
NO
26
Brake fluid sensor
ON/OFF
CLU
NO
27
Parking brake switch
ON/OFF
BCM,CLU
NO
28
Multifunction switch(Lighting)
ON/OFF
 -
NO
29
Hood switch
OFF/OPEN
BCM
YES
30
Trunk release switch
ON/OFF
BCM,SMK
YES

Relay output control
No
Relay output
Value
Type
Remarks
1
Auto cut
ON/OFF
Transistor
Auto cut of Dark current
2
Sound relay
ON/OFF
Transistor
 
3
Door lock relay
ON/OFF
LSD
 
4
Door unlock relay
ON/OFF
LSD
 
5
Power window main relay
ON/OFF
Transistor
 
6
Rear heater relay
ON/OFF
LSD
 
7
Front deicer relay
ON/OFF
LSD
 
8
Burglar alarm relay
ON/OFF
LSD
 
9
Burglar horn relay
ON/OFF
LSD
 
10
T/TURN and D/LOCK
ON/OFF
LSD
 
11
Trunk lid relay
ON/OFF
Transistor
 

Lamp control
No
Lamp
Bulb capacity
PWM control
PCL detection
OCL detection
1
Head lamp High(Left)
55 W
O
O
 
2
Head lamp Low(Left)
55 W
O
O
 
3
Rear turn signal(Left)
33 W
 
O
O
4
Front turn signal(Left)
28 W
 
O
O
5
Head lamp High(Right)
55 W
O
O
 
6
Head lamp Low(Right)
55 W
O
O
 
7
Rear turn signal(Right)
33 W
 
O
O
8
Front turn signal(Right)
28 W
 
O
O
9
Tail lamp(Left, right)
72 W
 
O
 
10
Interior tail lamp
60 W
 
O
 
11
Front fog lamp(Left, right)
70W(35W+35W)
O
O
 

*PCL(Programmable Current Limit) : It detects the current of lamp. If a current exceed the standard value, it cuts the current of lamp.
*OCL(Open Circuit Limit) : It detects the current of lamp. If a current is below the standard value, it controls current of lamp.
Auto cut system of dark current

1.
Description : It cuts automatically power to be provided with load for reducing useless dark current according to vehicle state.

2.
SJB had 3 modes, "Normal Mode", "Sleep Mode", "Power Off Mode". Auto cut of dark current practice in "Sleep Mode".
A.
"Sleep" condition : IG OFF, constant input switch, CAN network doesn't activate.
B.
"Sleep" resolutive condition : Any switch inputs, CAN network activates, KEY ON, IGN ON
C.
"Power OFF" condition : The setting time of timer which is used by cutting a load power expires.
D.
"Normal Mode" : SJB function normally activates.
E.
"Sleep Mode" : It is low power mode and activates for reducing electricity consumption of SJB or IPM. Auto cut of dark current function activates.
F.
"Power OFF Mode" : Power of MCU and circumferential circuit is cut for minimizing electricity consumption. Operation stops.
3.
The explanation - The auto cut of dark current

Before delivering to customer
Fuse Switch
•All door close & RKE door lock or Constant switch state
(Auto cut of dark current scenario starts.)
 -After "sleep" state is for 20 min.
 -SJB power down(SJB dark current : 200 μA) and cutting power of Lamp/Body Load/Wake up

After delivering to customer
Fuse Switch
•All door close & Constant switch state : C_BAState=OFF
(Auto cut of dark current scenario starts.)
 -After "sleep" state is for 20 min.
 -SJB power down(SJB dark current : 200 μA) and cutting power of Lamp Load
•In case RKE door lock : C_BAState=ON & Trunk SW=CLOSE
(Auto cut of dark current scenario starts.)
 -After "Sleep" state 35s~65s (Waiting time of other unit : 30~60s + SJB sleep counts 5s)
 -SJB Powerdown(SJB dark current : 200 μA) and cutting power of Lamp Load


4.
Problem when fuse switch setting is wrong
: If a fuse switch is set to OFF(Before delivering to customer) by a customer or technician and auto cut function of dark current activates, below problems may happen.
Symptom
Related part
•Door lock/unlock, trunk open don't activate by RKE.
(Wakeup of each module don't activate.)
BCM
•Digital clock is reset.(Memory is reset.)
Digital clock
•Setting value of audio(Volume, Frequency setting) is reset.
(Memory is reset.)
Audio

*If fuse switch OFF(before delivering to customer) is set, power of BCM, Digital clock and audio is shut off.