Hyundai Creta: Fuses And Relays / Junction Box (Passenger Compartment)

Components and components location

Component Location
Smart Junction Block

Description and operation

Communication Network Diagram

4WD Control Unit
Aircon Control
Airbag Control Unit
Body Controller Area Network
Body Control Module
Chassis Controller Area Network
Cluster Module
Engine Control Unit
Motor Driven Power Steering
Steering Angle Sensor
Smart Junction Block
Smart Key Unit
Telematics Unit
Rear View Camera

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
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
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
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.
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.

Repair procedures

Fuse Inspection
Be sure there is no play in the fuse holders, and that the fuses are held securely.
Are the fuse capacities for each circuit correct?
Are there any blown fuses?
If a fuse is to be replaced, be sure to use a new fuse of the same capacity. Always determine why the fuse blew first and completely eliminate the problem before installing a new fuse.
The SJB can be diagnosed by using the GDS. The SJB communicates with the GDS which then displays inputs and outputs along with codes.
To diagnose the SJB function, select the vehicle model, BCM and SJB.

To consult the present input/out value of SJB, "Current Data". It provides information of SJB input/output conditions.

To perform functional test on SJB outputs, select "Actuation Test"

Passenger Compartment Junction Block (SJB)
Disconnect the negative (-) battery terminal.
Remove the crash pad lower panel.
(Refer to Body - "Crash Pad Lower Panel")
Disconnect the connectors from the fuse side of the smart junction block.
Remove the smart junction block (A) after loosening the mounting nuts (2EA).

Disconnect the connectors from the back side of the smart junction block.
Install the smart junction block.
Install the crash pad lower panel.
Check that all system operates normally.
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Indicators And Gauges

Other information:

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Hyundai Creta GS 2014-2024 Service Manual: Description and operation
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