Kia Forte: Relay Box (Passenger Compartment) Description
Smart Junction Box(SJB)
1. |
General function : Interior Junction Box + some functions of BCM
It controls loads with CAN communication and IPS.
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2. |
Main function
A. |
Low speed CAN communication(100 kbps)
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B. |
Self diagnostics(Lamp open/short)
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C. |
Fail safe(When MCU/CAN is fail, Head lamp / Tail lamp
directly drive)
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D. |
Protection of bulb over-voltage(PWM function)
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E. |
Cut of Over-load and Short : PCL(Program Current Limit)
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Auto cut system of dark current
![](images/books/1305/sydbe4103n.gif)
1. |
Description : It cuts automatically power to be provided with
load for reducing useless dark current according to vehicle state.
![](images/books/1305/sgdbe2199e.gif)
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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.
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B. |
"Sleep" resolutive condition : Any switch inputs, CAN
network activates, KEY ON, IGN ON
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C. |
"Power OFF" condition : The setting time of timer which
is used by cutting a load power expires.
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D. |
"Normal Mode" : SJB function normally activates.
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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.
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F. |
"Power OFF Mode" : Power of MCU and circumferential circuit
is cut for minimizing electricity consumption. Operation stops.
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3. |
The explanation - The auto cut of dark current
![](images/books/1305/smdbe1079n.gif)
Before delivering to customer
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Fuse Switch
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•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
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![](images/books/1305/smdbe1387d.gif)
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After delivering to customer
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Fuse Switch
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•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
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![](images/books/1305/smdbe1388d.gif)
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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
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Related part
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•Door lock/unlock, trunk open don't activate by
RKE.
(Wakeup of each module don't activate.)
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BCM
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•Digital clock is reset.(Memory is reset.)
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Digital clock
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•Setting value of audio(Volume, Frequency setting)
is reset.
(Memory is reset.)
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Audio
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*If fuse switch OFF(before delivering to customer) is set, power
of BCM, Digital clock and audio is shut off.
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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? ...