Hyundai Elantra: Fuses And Relays / Relay Box (Passenger Compartment) Description and Operation

Hyundai Elantra AD (2016-2020) Service Manual / Body Electrical System / Fuses And Relays / Relay Box (Passenger Compartment) Description and Operation

Auto Cut System of Dark Current

Airbag Control Unit
Assist Door Module
Body Controller Area Network
Body Control Module
Blind Spot Detection
Chassis Controller Area Network
Cluster Module
Dual Automatic Temp Control
Driver Door Module
Electronic Stability Program
Engine Management System
Lane Keeping Assist System
Multi media Controller Area Network
Motor Driven Power Steering
Powertrain Controller Area Network
Power Seat Module
Steering Angle Sensor
Smart Junction Block
Smart Key Unit
Parking Assist System
Transmission Control Unit
Tire Pressure Monitoring System
Vehicle Dynamic Control
Telematics System
Anti-lock Brake System
Smart Cruise Control

Smart Junction Block (SJB)
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
Assist seat belt switch
Assist the door switch
Driver's seat belt switch
Rear left door switch
Rear right door switch
IGN1 switch
IGN2 switch
Brake fluid sensor
Trunk lid handle switch
HID head lamp option
Hazard lamp switch
Head lamp low beams switch
Hood switch
Left front / rear turn signal switch
Right front / rear turn signal switch
Parking brake switch
Driver the door lock/unlock control status
Assist the door lock/unlock control status
Rear left the door lock/unlock status
Rear right the door lock/unlock status
Driver the door switch
Driver the door key lock switch
Driver the door key unlock switch
Driver the door power window lock switch
Driver the door power window unlock switch
Left Head lamp low beams
Right Head lamp low beams
Left Head lamp high beams
Right Head lamp high beams
Room lamp
Exterior left tail lamp
Exterior right tail lamp
Left front / rear turn signals
Right front / rear turn signals
DRL left lamp
DRL right lamp
Body resistance cut control
Front left turn signal output
Front right turn signal output
Relay Control
Rear glass heater relay
Trunk lid relay
Front glass heater relay
Head lamp high beams relay
Memory fuse switch relay
Door lock/unlock relay
Power window wake-up relay
2 Turn door lock 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.
OCL (Open Current Limit)
Detect the lamp open state and inform the user of it.
How to operate: Detect the current of the lamp and if it is below the standard level, change the lamp operation.
Applied load: Applied to the turn signal lamp 4 channel
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 ?A) and cutting power of Lamp
/Multimedia 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.
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)

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.
Related part
Door lock/unlock, trunk open don't activate by RKE.
(Wakeup of each module don't activate.)
Digital clock is reset.(Memory is reset.)
Digital clock
Setting value of audio(Volume, Frequency setting) is reset.
(Memory is reset.)

* If fuse switch OFF (before delivering to customer) is set, power of BCM, Digital clock and audio is shut off.
Relay Box (Passenger Compartment) Components and Components Location
Component Location Interior Junction Block ...

Relay Box (Passenger Compartment) Repair procedures
Fuse Inspection 1. Be sure there is no play in the fuse holders, and that the fuses are held securely. 2. Are the fuse capacities for each circuit correct? 3. Are there any blown fuses? ...

Other information:

Hyundai Elantra AD (2016-2020) Service Manual: Trunk Lid Assembly Repair procedures
Replacement     • Put on gloves to prevent hand injuries.     • When removing and installing the trunk lid, an assistant is necessary . • Be careful not to damage the trunk lid and body surface. 1. Remove the trunk lid trim. ...

Hyundai Elantra AD (2016-2020) Owners Manual: Drive Mode Integrated Control System
The drive mode may be selected according to the driver's preference or road condition. Information If there is a problem with the instrument cluster, the drive mode will be in NORMAL mode and may not change to SPORT mode. The mode changes, as below, whenever the DRIVE MODE button is press ...

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