Integrated Central Control Unit (ICU)

Components and Component Location

Component Location

Description and Operation

Description

Communication Network Diagram

Integrated Central Control Unit (ICU)

The ICU (Integrated Central Control Unit) is an integrated intelligent junction block and central gateway.

It performs the function of a conventional "Smart Junction Block" and the function of a "Central Gateway" communication device.

Central Gateway (CGW)

The CGW is a controller that provides communication between controllers connected to different networks.

Five CAN networks are connected to the CGW. B-CAN and M-CAN are connected to low-speed CAN, and C-CAN and P-CAN are connected to high-speed CAN. D-CAN is connected for inspection.

1. 1

   CGW Main Specifications

   1. Routing: Exchanges information between different vehicle communication networks.

      

   2. Network Security Control: Allows only inspection communication (D-CAN) to connect to the vehicle network to prevent

      

   3. Additional Functions

      • If the warning lamp is on, perform remote diagnosis of the chassis CAN (C-CAN) system via the I-Box and gateway.

      • Dark Current Measurement: After sending a forced electronic shutdown message for each network from the diagnostic equipment, the gateway also enters sleep mode.

      • Current operation check: check the problem while the electronic parts are operating.

   4. Diagnose the malfunction when a CAN communication signal failure occurs in the communication line / control defect.

      (CGW records a DTC for the controller with the transmission error.)

2. 2

   How to Check the CGW

   1. Although the record "No CGW CAN signal (TIMEOUT)" appears during inspection, the malfunction code of the faulty electronic component must never be determined as a CGW failure. CGW is the controller that serves as an intermediary between the transmitting and receiving controllers in the vehicle. If one of the following two cases occurs: (1) the transmitting controller cannot send a message to CGW, so CGW cannot send it to the receiving controller; (2) CGW sends a predefined value (Timeout Value), and the receiving controller records a malfunction code for message transmission failure. Therefore, to finally identify the controller that cannot send the CAN signal, the CGW DTC must be checked. CGW records a DTC only when it cannot receive a signal for more than 10 seconds after KEY ON. To determine the cause of the absence of CAN signal transmission, the CGW DTC must be checked after waiting more than 20 seconds with KEY ON.

   2. If the CAN communication control unit is not reinstalled after removal from the vehicle, CGW records the "No CAN signal" malfunction code for the unit.

      If the malfunction code remains after replacing the electronic components and the malfunction code is not erased, check whether the connector of the electronic component is damaged and whether it is connected correctly, and whether the CAN bus wiring of the controller is operating normally. If the removed electronic component cannot be reinstalled, the "Erase Expected Network Configuration" service must be performed. Refer to the DTC troubleshooting manual for the execution method of each malfunction code service.

      Otherwise, the "No CAN signal" malfunction code on the corresponding controller may not be erased.

   3. IGN2 SJB is turned on when the MCU has failed (inoperative state due to external physical or electrical impact). To ensure driver safety, the low beam headlamps, external and internal rear lamps are forcibly turned on when the low beam headlamp switch is ON.

   4. IGN2 is turned on when data transmission/reception is impossible due to a failure in the CAN communication line (both cables shorted high/low, BAT shorted high/low, GND shorted high/low). In case of a fault in the CAN communication line connected to the SJB module, when the headlamp low beam switch is ON, the low beam headlamps and internal/external rear lamps are forcibly turned on.

Smart Junction Block (SJB)

The Smart Junction Block (SJB) is a module that performs the function of a conventional junction box and some IBU functions.

It controls various components, including lamps, using CAN communication and IPS (which replaces the function of fuses and relays) or ARISU.

IPS stands for Intelligent Power Switch, which uses semiconductor technology to replace the current role of fuses and relays.

The IPS chip performs two functions:

1) controls high-current components;

2) protects components from overcurrent.

SJB Control Input

1. 1

   Switch Signal Input

   1. Auxiliary Seat Belt Switch

      Seat Belt Unfastened Reminder Switch

      Door Switch Assist

      Driver Seat Belt Switch

      Driver Seat Belt Switch

      Rear Left Seat Door Switch

      Rear Right Seat Door Switch

      Rear Left Seat Belt Switch

      Rear Right Seat Belt Switch

      Rear Center Seat Belt Switch

      IGN1 Switch

      IGN2 Switch

      Brake Fluid Sensor

      Trunk Opener Switch

      Trunk Lid Handle Switch

      HID Headlamp (Option)

      ADV HID Headlamp Option

      Hazard Warning Switch

      Headlamp Low Beam Switch

      Hood Switch

      Dark Switch

      Front/Rear Left Turn Signal Switch

      Front/Rear Right Turn Signal Switch

   2. IPS&ARISU

      Left Headlamp Low Beam

      Right Headlamp Low Beam

      Right Headlamp High Beam

      Right Headlamp High Beam

      Front Left/Right Fog Lamp

      License Plate Lamp

      Outer Left Rear Lamp

      Rear Exterior Lighting Lamp

      Left Front/Rear Turn Signal Lamps

      Right Front/Rear Turn Signal Lamps

      Static Cornering Left Lamp

      Static Cornering Right Lamp

      Left DRL Lamp

      Right DRL Lamp

      Trunk Lamp

      Body Resistance Cut Control

      Front Left Turn Signal Output

      Front Right Turn Signal Output

   3. Relay Control

      Rear window defrost relay

      Anti-Theft Alarm Horn Relay

      Trunk Lid Relay

      Interior Lamp Relay

      Windshield Heater Relay

      Rear Fog Lamp Relay

      High Beam Headlamp Relay

2. 2

   SJB Protection

   1. PCL (Programmable Current Limiter) Functions

      • PCL replaces the protective function of the junction box wiring.

      • How it works: If the lamp current exceeds the standard level, cut off the current to protect the lamp.

      • Lamp shut-off time: 300 ms or less.

      • Components used: all lamp components are controlled by the SJB.

      • Output the DTC according to the fault detection condition.

   2. OCL (Open Current Limit)

      • OCL detects the open state of the lamp and informs the user of this.

      • How it works: Detect the lamp current and, if it is below the standard level, change the lamp operating mode.

      • Components used: 4 turn signal lamps

      • Output the DTC according to the fault detection condition.

3. 3

   SJB Fail-Safe Function

   1. When the MCU has failed (inoperative due to physical or electrical impact from outside), and the IGN2 and headlamp low beam switch are ON, the SJB turns on the low beam headlamps and external/internal rear lamps to ensure driver safety.

   2. When data transmission/reception fails due to a failure of the CAN communication line connected to the SJB module (both high and low lines open, high/low BAT short, high/low GND short), the low beam headlamps and internal/external rear lamps are forcibly turned on if IGN2 is ON and the headlamp low beam switch is ON.

4. 4

   Battery Saver Auto Shut-Off System

   1. Description: Automatically cuts off power supplied to components 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".

      • Sleep state: IG OFF, constant input switch, CAN network is not activated.

      • Deciding condition "Sleep": any switch input, CAN network activated, KEY ON, IGN ON

      • "Power Off" condition: timer setting time, which is used by cutting off the load; power expires.

      • "Normal Mode": The SJB function is normally active.

      • "Sleep mode": a low power consumption mode that is activated to reduce power consumption of the SJB or IPM. The dark current cut-off function is automatically activated.

      • "Power-down 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 ignition switch status (Automatic dark current cut-off scenario starts.) After the "sleep" state, the state lasts 20 min. SJB power-off (SJB dark current: 200 µA) and lamp load cut-off /Body load/Wake-up

      
      

      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 the "sleep" state, the state lasts 20 min. SJB power-off (SJB dark current: 200 µA) and lamp load cut-off For RKE door lock: C_BAState=ON & Trunk Status=CLOSE (Automatic dark current cut-off scenario starts.) After "Sleep" state 35 s–65 s (standby time other unit: 30–60 s + SJB sleep is considered 5 s) SJB Power-down (SJB dark current: 200 µA) and cut-off Lamp load

   4. Problem due to incorrect installation of the fuse switch

      : If the fuse switch is set to OFF (before delivery to the customer) by the customer or a service technician and the dark current automatic cut-off function is activated, the following problems may occur.

      Symptom	Related Part
      Door lock/unlock and trunk opening are not activated by RKE. (Wake-up of each module is not activated.)	IBU
      Digital clock is reset. (Memory is reset.)	Digital Clock
      Sound setting values (volume, frequency setting) are reset. (Memory is reset.)	Audio

      
      

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

Repair Procedures

Fuse Inspection

1. 1

   Make sure the fuse holders are secured firmly and the fuses are securely held in place by the holders.

2. 2

   Make sure that each fuse circuit has the correct fuse rating.

3. 3

   Inspect the fuses for damage.

Diagnosis Using KDS

1. 1

   In the body electrical system, faults can be quickly diagnosed using the Korean Diagnostic System (KDS).

   The Diagnostic System (KDS) provides the following information.

   1. Self-diagnosis: check for malfunction and diagnostic trouble code (DTC).

   2. Current Data: Check the system input/output status.

   3. Operation check: Check the operating status of the system.

   4. Special Function: Control of other functions, including parameter setting and zero point adjustment.

2. 2

   Select "Vehicle Model" and "Integrated Central Control Unit (ICU)" to inspect the vehicle using the tester.

3. 3

   Select the "Current Data" menu to view the current input/output data status.

4. 4

   To forcibly activate the input value of the module under test, select the "Activation Test" option.

5. 5

   To change a user setting, select "User Setting".

Removal

1. 1

   Disconnect the negative (-) battery terminal.

2. 2

   Remove the airbag lower panel.

   (Refer to Body - "Under Cover Panel")

3. 3

   Remove the side switch assembly (A) of the airbag after loosening the mounting screws.

   

4. 4

   Disconnect the connector of the airbag side switch assembly (A).

   

5. 5

   Remove the ICU (A) by loosening the nuts after disconnecting the connector.

   

6. 6

   Disconnect the connector (A) from the ICU.

   

Installation

1. Install in the reverse order of removal.