Abbreviation | Explanation |
4WD_ECU | 4WD Control Unit |
A/CON | Aircon Control |
ACU | Airbag Control Unit |
B_CAN | Body Controller Area Network |
BCM | Body Control Module |
C_CAN | Chassis Controller Area Network |
CLU | Cluster Module |
ECU | Engine Control Unit |
MDPS | Motor Driven Power Steering |
SAS | Steering Angle Sensor |
SJB | Smart Junction Block |
SMK | Smart Key Unit |
TMU | Telematics Unit |
RR_CAM | Rear View Camera |
General function : Interior Junction Block + some functions of BCM
It controls loads with CAN communication and IPS.
IPS stands for Intelligent Power Switch, which uses the semiconductor technology to replace the current role of fuse and relay. (The IPS device protects the current load control function from the overcurrent.)
The advantages of IPS are as follows:
Reduce relay and consequently decrease weight and volume
Remove the relay operation noise
Not necessary to replace fuse, increasing the product life
Diagnosis capability
SJB control entry
Switch signal input
Parking brake switch
Driver door switch
Assist door switch
Rear left door switch
Rear right door switch
Driver door unlock switch
Assist door unlock switch
Rear left door unlock switch
Rear right door unlock switch
Driver/Assist the door key lock switch
Driver/Assist the door key unlock switch
Tailgate release switch
Tailgate switch
Driver's seat belt switch
Assist seat belt switch
Center door lock switch
Center door unlock switch
Head lamp low switch
Hood switch
Stop switch
Assist seat belt reminder mat switch
Brake fluid sensor switch
IPS & ARISU
Left/Right Head lamp low beams
Left/Right Head lamp high beams
Left/Right Head lamp BI-Function
Exterior left/right tail lamp
Front left/right foglamp
Rear left/right foglamp
Left/Right DRL lamp
Left/Right Stop lamp
Interior tail lamp
HMSL
Relay Control
Door lock relay
Door unlock relay
Tailgate unlock relay
Power window relay
Power outlet relay
Rear windshield deicer relay
IOD relay
SJB protection
PCL (Programmable Current Limit) functions
Replace the current junction box fuse function to protect the wire.
How to operate : If the lamp current exceeds the standard level, cut off the lamp current to protect lamp.
Lamp cut off time : 300ms or less.
Applied load : Applied to all lamp loads controlled by SJB.
Output the error code according to the error detection conditions.
SJB fail safe function
When SJB has a failed MCU (not operating due to a physical or electrical shock from the outside), the head lamp low and exterior and interior tail lamp are turned on to secure the driver if IGN2 is on and the head lamp low switch is on.
When the data transmission/reception fails due to a failed CAN communication line connected with SJB module (disconnection of both high and low line, high/low BAT short, high/low GND short), the head lamp low and interior/exterior tail lamps are turned on if IGN2 is on and the head lamp low switch is on.
Auto Cut System of Dark Current
Description : It cuts automatically power to be provided with load for reducing useless dark current according to vehicle state.
SJB had 3 modes, "Normal Mode", "Sleep Mode", "Power Off Mode". Auto cut of dark current practice in "Sleep Mode".
"Sleep" condition : IG OFF, constant input switch, CAN network doesn't activate.
"Sleep" resolutive condition : Any switch inputs, CAN network activates, KEY ON, IGN ON
"Power OFF" condition : The setting time of timer which is used by cutting a load power expires.
"Normal Mode" : SJB function normally activates.
"Sleep Mode" : It is low power mode and activates for reducing electricity consumption of SJB or IPM. Auto cut of dark current function activates.
"Power OFF Mode" : Power of MCU and circumferential circuit is cut for minimizing electricity consumption. Operation stops.
The explanation - The auto cut of dark current
Before delivering to customer | Fuse switch OFF |
● All door close & RKE door lock or Constant switch state (Auto cut of dark current scenario starts.) - After "sleep" state is for 5 min. - SJB power down(SJB dark current : 200 μA) and cutting power of Lamp /Body Load/Wake up/Immobilzer | ![]() |
After delivering to customer | Fuse switch ON |
● 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.) - SJB cut power of Lamp Load after 5 sec regardless of "sleep" state - After "Sleep" state, SJB Powerdown(SJB dark current : 200uA) | ![]() |
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.