Hyundai Elantra AD Quiz
Body Electrical System

Relay Box (Interior) Description and Operation

In this manual: Body Electrical System
General Information — 9Engine Mechanical System — 84Engine Electrical System — 60Emission Control System — 24Engine Control System/Fuel System — 90Automatic Transmission — 92Drive Shaft and Axle — 20Suspension System — 31Steering — 20Restraints — 50Brake System — 63Body (Interior and Exterior) — 214Body Electrical System — 221Heating, Ventilation, and Air Conditioning — 71
4steps
~24min
2/5difficulty
Done 0 of 4

Description

Battery Saver Auto Shut-Off System
Abbreviation Description
ACU Airbag Control Unit
ADM Assist Door Module
B_CAN Body Controller Network
BCM Body Control Module
BSD Blind Spot Detection
C_CAN Chassis Controller Area Network
CLU Cluster Module
DATC Dual Automatic Temperature Control
DDM Driver door module
ESC Electronic Stability Program
Emergency Call Engine Control System
LKAS Lane Keeping Assist System
M_CAN Multimedia Controller Network
MDPS Motor Driven Power Steering
P_CAN Power Train Controller Area Network
PSM Power Seat Module
CAC Steering Wheel Angle Sensor
SJB Smart Junction Box
SMK Smart Key Unit
PAS Park Assist System
TCU Transmission Control Unit
SCP Tire Pressure Monitoring System
VDC Vehicle Dynamic Control
TMU Telematics System
ABS Anti-Lock Braking System (ABS)
CCS Smart Cruise Control

Smart Junction Box (SJB) General Function: Interior Junction Block + some BCM functions. It controls loads through CAN communication and IPS.
IPS stands for Intelligent Power Switch, which uses semiconductor technology to replace the current role of fuses and relays. (The IPS device protects the load control function against overcurrent.)
The advantages of IPS are as follows:
  • Reduces the number of relays, and therefore reduces weight and size
  • Eliminates relay operating noise
  • No need to replace fuses, extending product service life.
  • Diagnostic capability
SJB Control Input
  1. Switch Signal Input
    1. Assist Seat Belt Switch, Door Switch, Driver Seat Belt Switch, Rear Left Door Switch, Rear Right Door Switch, IGN1 Switch, IGN2 Switch, Brake Fluid Level Sensor, Trunk Lid Handle Switch, HID Headlamp (Option), Hazard Lamp Switch, Low Beam Headlamp Switch, Hood Switch, Left Front/Rear Turn Signal Switch, Right Front/Rear Turn Signal Switch, Parking Brake Switch, Driver Door Lock/Unlock Control Status, Assist Door Lock/Unlock Control, Rear Left Door Lock/Unlock Status, Rear Right Door Lock/Unlock Status, Driver Door Switch, Driver Door Lock Switch, Driver Door Key Unlock Switch, Driver Door Window Lock Switch, Driver Door Window Unlock Switch
    2. IPS & ARISU: Left Headlamp Low Beam, Right Headlamp Low Beam, Left Headlamp High Beam, Right Headlamp High Beam, Room Lamp, Outside Left Tail Lamp, Outside Right Tail Lamp, Left Front/Rear Turn Signal, Right Front/Rear Turn Signal, DRL Left Lamp, DRL Right Lamp, Body Cut Resistance Control, Front Left Turn Signal Output, Front Right Turn Signal Output
    3. Relay Control: Rear Window Defroster Relay, Trunk Lid Relay, Windshield Defroster Relay, Headlamp High Beam Relay, Memory Fuse Relay, Door Lock/Unlock Relay, Power Window Wake-Up Relay 2, Door Lock Turn Relay
  2. SJB Protection
    1. PCL (Programmable Current Limiter) Functions
      A. Replaces the current fuse function of the junction block to protect the wire.
      B. Operation: If the lamp current exceeds the standard level, cut off the lamp current to protect the lamp.
      C. Lamp shut-off time: 300 ms or less.
      D. Applied load: Applies to all lamp loads controlled by the SJB.
      E. Output a fault code according to the fault detection conditions.
    2. OCL (Open Current Limit)
      A. Detects an open lamp condition and informs the user.
      B. Operation: Determine the lamp current and, if it is below the standard level, change the lamp operating mode.
      C. Applied load: Applies to the 4-channel turn signal lamp.
      D. Output a fault code according to the fault detection conditions.
  3. SJB Fail-Safe Function
    1. When the SJB has a faulty MCU (not operating due to physical damage or electric shock from outside), the low beam headlamps and the outside and inside tail lamps are turned on to ensure driver safety if IGN2 is on and the low beam headlamp switch is on.
    2. If communication fails due to a CAN communication line fault connected to the SJB (open in both CAN High and CAN Low lines, CAN High/Low short to BAT, CAN High/Low short to GND), the low beam headlamps and the interior/exterior rear lamps turn on when IGN2 is on and the low beam headlamp switch is on.
  4. Battery Saver Auto Shut-Off System
    1. Description: Automatically cuts off the power supplied to loads in order to reduce unnecessary dark current, depending on the vehicle condition.
    2. The SJB has 3 modes: "Normal Mode", "Sleep Mode", and "Power Off Mode". The automatic dark current cut-off control is performed in "Sleep Mode".
      A. "Sleep" condition: IG OFF, no constant input switch, CAN network not active.
      B. Sleep cancellation conditions: any input switch, CAN network activation, KEY ON, IGN ON.
      C. "Power Off" condition: the timer set for cutting off the load power has expired.
      D. "Normal Mode": The SJB function is normally active.
      E. "Sleep Mode": This is a low power consumption mode that is activated to reduce the power consumption of the SJB or IPM. The automatic dark current cut-off function is activated.
      F. "Power Off Mode": Power to the MCU and the circuit is cut off to minimize power consumption. Operation stops.
    3. Description - Automatic Dark Current Cut-off
      Before Delivery to Customer Fuse switch OFF.
      • All doors closed and door lock RKE or constant switch status (Automatic dark current cut-off scenario starts.)
      • After "Sleep" condition for 5 min.
      • Power cut-off of SJB (SJB dark current: 200 μA) and power cut-off of lamp / multimedia download / wake-up / immobilizer.

      After Delivery to Customer Fuse switch ON.
      • All doors closed and constant switch status: C_BAState=OFF (Automatic dark current cut-off scenario starts.)
      • After "Sleep" condition for 20 min.
      • In case of RKE door lock: C_BAState=ON & Trunk SW=CLOSE (Automatic dark current cut-off scenario starts.)
      • After "Sleep" condition for 35–65 s (waiting time for other device: 30–60 s + SJB sleep counted as 5 s).
    4. Problem when the fuse switch is incorrectly set: If the fuse switch is set to OFF (before delivery to the customer) by the customer or a technician, and the automatic dark current cut-off function is activated, the following problems may occur.
      Symptom Related Part
      • Door lock/unlock and trunk opening by RKE are not activated. (Wake-up of each module is not activated.)
      		 BCM
      • Digital clock is reset. (Memory is reset.)
      		 Digital Clock
      • Audio setting values (volume, frequency) are reset. (Memory is reset.)
      		 Audio

      * If the fuse switch is turned OFF (before delivery to the customer), power to the BCM, digital clock and audio is cut off.

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