BCM SJB Introduction 1.1 History 1.2 Inputoutput Interface 1.3 IPS Function 2. BCM SJB Control 2.1 Main Functions 2.2 Wiper Control 2.3 Lamp Control 2.4 Central Door LockUnlock Control 2.5 Miscellaneous Controls 3. Service Procedure Function 2 BCM SJB Control 2 1 Main Functions 2 2 Wiper Contro.
Module Body Electrical Control System Learning Objectives Describe the history and features of the body control module Describe the body control module's control functions and processes Perform body control module service procedures BCM & SJB Introduction 1.1 History 1.2 Input/output Interface 1.3 IPS Function BCM & SJB Control 2.1 Main Functions 2.2 Wiper Control 2.3 Lamp Control 2.4 Central Door Lock/Unlock Control 2.5 Miscellaneous Controls Service Procedure System Introduction 1.1 System History Body electrical systems were developed for the speedy control of modules required for the application of various convenience functions in vehicles The Body Electrical System is the system that provides integrated control for various convenient features of a vehicle It supports controls for the wiper system, lamp system, central door lock/unlock system, and theft alarm system The history of body electrical systems is summarized below 1) ETACS ETACS is the acronym for Electronic Time Alarm Control System Its controls the timer (heating wire timer and power window timer), alarm (seat belt alarm, door open alarm, etc.), lamps and door lock Vehicles with an ETACS receive all switch data related to body electrical system control through the ETACS Relay, actuator and motor control was also performed by the ETACS Communication with diagnostic equipment is not possible as no communication IC is installed ETACS is not used in modern vehicles 2) BCM BCM is the acronym for Body Control Module It is the successor to the ETACS Its difference from the ETACS is that communication with diagnostic equipment is possible Although individual vehicles models vary, the control of a BCM is similar to that of an ETACS Diagnostic equipment communication allows the viewing of current data on input/output elements, and actuation tests can be carried out 3) BCM + SJB As BCMs started to use CAN communication and more functions became required of them, the SJB (Smart Junction Box) was applied to BCMs Like BCMs, SJBs receive switch data and drive actuators A SJB is connected to a BCM via CAN communication to receive BCM commands and drive actuators The BCM + SJB combination is the most common body electrical system used today 4) IPM IPM is the acronym for Intelligent Integrated Platform Module, which combines all the functions of a BCM and SJB Switch signals are received from modules related to control functions for actuator output IPMs are mainly found in luxury vehicles 10 1.2 Input/output Interface The most important function of a body electrical system is receiving switch signals and producing an appropriate output The input and output of signals is closely related to Basic Electrics and Electronics Take a look at the following diagram Power Switch 5V TR C P U Relay B+ Power Ground 1) Input Switch input shows that voltage of 5V is sent to the switch from the body electrical system If the switch operates, the pull-up voltage of 5V falls to 0V The BCM detects this voltage drop and recognizes the switch operation This is called the pull-up method As explained in Basic Electrics and Electronics, there is also the pull-down method, which immediately inputs 12V upon switch operation, in addition to the pull-up method 2) Output Upon switch input detection, the body electrical system must drive the relays to switch on the lamps The body electrical system sends output currents to the transistor to drive the transistor that controls the relays When the transistor switches on, the relays become magnetized and lamps operate If output is executed by a module other than the one that detected the switch signal, the "switch on" signal is sent to the module responsible for output through the communication line The system's input/output components increased significantly as a vehicle's control features increased The trend in recent models is the change from the ground output control using transistor to power output control using the IPS to actively respond to potential problems created at the output terminal In short, a body electrical system controls output when input conditions are met The pull-up method and pull-down method are mainly used for input monitoring Output control takes place through transistor-based relay ground control or IPS-based control 11 1.3 IPS IPS stands for Intelligent Power Switching device, which is an output device that can replace a relay and fuse IPS uses a semiconductor device and is being widely applied to body electrical system output control In addition to output control, IPS can detect and manage a circuit disconnection, short circuit or overload Other features include a self-check function, compact size and multi-channel control Currently, IPS is being widely used for smart + = junction box output control An IPM can also Relay use an IPS for output control + fuse = IPS IPS is mainly used for the control of vehicle lamp (head lamps, indicators, tail lamps and fog lamps) output The key functions of IPS are as follows A device that integrates four IPS units Performs the function of four IPS units simultaneously 4As four IPS units are combined into a single package, there is ample space and simplified software is used 1) Wiring protection PCL (Programmable Circuit Limit) function Fuse is removed on IPS applied circuit IPS directly detects the current flowing through the circuit and, if over current is detected, the IPS cuts off power to the corresponding circuit Category Application Range Current detection Deactivation Conditions Description All the lamp loads controlled by IPS (head lamp, fog lamp, tail lamp) If over current flows, cuts off the power within 300 ms and record the event for diagnosis When the shut off switch returns to On (when no over current is detected), after the lamp switch where over current is detected has been turned Off When the switch returns to On after IGN Off (when no over current is detected) The following diagram shows how IPS detects and cuts off overcurrents 12 Fuse and relay control IPS Control Interior junction box SJB ⓒ Fuse Disconnection B+ B+ ⓑ Overcurrent flow ⓓ Prevent control if overcurrent is detected and record Lamp status ⓒ Transmit current information ⓐ Short circuit MCU ⓐ Short circuit ⓑ Overcurrent flow BCM In the case where a fuse was used, it got disconnected from an overcurrent when a short circuit occurred in the lamp circuit The following is the application of an IPS Circuit currents are constantly monitored by the IPS When an overcurrent is detected, data is sent to the controller of the SJB The SJB immediately stops IPS operation to prevent circuit damage OCL (Open Circuit Limit) function Different than the PCL, the OCL detects disconnection and notifies the driver if the circuit is disconnected OCL is applied to indicators and hazard lamps to speed up their blinking in the event of a lamp disconnection Category Application Range Current detection Deactivation Conditions Description The OCL is applied only to the turn signal lamp and hazard lamp, and detects the circuit disconnection (bulb out of socket) and controls the remaining bulbs to make them blink faster Detects disconnection when the current flowing in the turn signal lamp circuit is below A and records the occurrence for diagnosis When the shut off switch returns to On, after the lamp switch where disconnection was detected has been turned Off When the switch returns to On after IGN Off and normal current is detected If the lamp circuit gets disconnected while IPS is monitoring circuit currents, current detection will indicate As well, circuit disconnection data is sent to the SJB controller The SJB then blinks all the lamps except the disconnected one quickly to notify the user of the lamp failure 13 2) Overvoltage protection (PWM control) The voltage applied to the lamp varies depending on the generated voltage If the generated voltage is low, then there's not enough illumination, and if the generated voltage is high, then the life span of the lamp is shortened The SJB controls the PWM to keep input voltage at 13.2V to increase lamp life span Protection against surge voltage is applied to below devices Head lamp low LH/RH (The surge voltage protection feature is not applicable for HID option) Head lamp high LH/RH Front fog lamps (LH/RH) and tail lamps (LH/RH) PWM control is not required for HID lamps as they have a built-in voltage booster called Ballast B＋(surge voltage inlet) ☞ If less than 13.2V is inputted, PWM is not activated ADC Circuit Maintain 13.2V rated voltage IPS Controller SJB If the pulse width is narrow If the pulse width is wide 70% 50% 12V 12V 0V 0V 30% 50% If 12 V is controlled at 70% On and 30% Off as If 12 V is controlled at 50% On and 50% Off as shown in the diagram, the average voltage is shown in the diagram, the average voltage is maintained at approximately V maintained at approximately V ☞ Pulse Width Modulation (PWM) can maintain constant voltage by modulating the pulse width 14 Control 2.1 Main Functions of the Body Electrical System While body electrical systems differ by vehicle, they perform the following functions in general Category Function Seat belt warning, Seat belt reminder , Alarm buzzer Warning RPAS indicator/buzzer control, RKE teaching Sun roof open warning, Parking brake warning, Key reminder B/Alarm Timer Anti-theft control Rear defogger, Front deicer, Power window control Central door lock/unlock by switch/key/RKE/SMK, Key reminder Door Auto door lock (Shift from P, Vehicle speed 15kph) control Auto door unlock (Crash, Shift to P, Key out) control, Tailgate unlock Safety Ignition key interlock, ATM shift lock control Tail lamp control by switch / auto cut, Auto light EXT lamp Headlamp control by switch / auto light, escort control Puddle & Pocket lamp control, Hazard lamp, Fog lamp control INT lamp Wiper etc Room lamp delay control, Map lamp delay control Front wiper: intermittent, washer, mist Rear wiper: intermittent, washer, on/off AV unlock output, Auto mirror folding & unfolding The body electrical system controls the lamps, wipers, power door lock, timer and alarm In this lesson, some of the main control functions of the body electrical system will be explained 15 2.2 Wiper Control IG BCM Wiper Motor Parking LO Wiper Relay C U HI P Washer Motor R LO Off ● ● INT ● ● ● M ● ● ● ● ● LO Multifunction Switch HI Vertical: switch position W H I ● ● ● IG N M W INT INT T E ● ● ● ● ● ● ● Horizontal: Output terminal for switch position The table indicates internal burn-in for the switch position Wiper control takes place as follows The wipers are independently controlled by the BCM without the SJB When the LOW or HIGH function is used, power is supplied to the wiper motor without BCM intervention (In some vehicles, the wiper LOW and HIGH functions are also controlled by the BCM.) WIperINT and MIST functions are controlled by the BCM When the switch is operated, the BCM receives switch signals and operates the transistor that controls the wiper relay When the wiper relay becomes magnetized, IGN power is supplied to the motor after passing through the internal contact of the multi-function switch The windscreen washer function is also controlled by the BCM Positioning the switch to "washer" immediately activates the washer motor and the wipers are controlled at LOW speed by the BCM Regardless of the wipers' current position, when the wiper switch is set to "off," the wipers return to their original position This function is in place to prevent the wipers from stopping in the middle of movement when the switch is set to "off." When the wipers are operating, the parking switch inside the wiper motor is always mechanically connected to IG power This keeps supplying power to the wiper motor even when the switch is set to "off." When the wipers return to their original position, the parking switch connects to the ground mechanically and cuts off power to the motor 16 2.3 Lamp Control 1) Tail Lamp & Head Lamp Control Ambient Light Sensor Cluster SJB Tail lamp switch Lamp Control request Head lamp LOW switch Head lamp HIGH switch SJB Control Signal Tail Lamp IPS CPU BCM IPS Lamp output completion signal Autolight switch Head Current Value Feedback & failure information lamp LOW and HIGH switch signals for the tail lamps and head lamps are detected by the BCM The BCM give IPS output commands to the SJB through B-CAN communication Then, the SJB produces tail/head lamp output through the IPS The SJB sends an output completion signal to the BCM to determine system soundness At the same time, data is sent to the cluster through CAN communication to light up the indicators If an auto light function is present, auto light switch signals are also detected by the BCM If the light level sensor reading sent to the BCM indicates that lamps need switching on, the BCM sends an IPS output command to the SJB to switch on the lamps 2) Indicators & Hazard Lamp Control SJB Lamp Control request Front left turn signal lamp BCM Rear left turn signal lamp IPS Control Front right turn signal lamp CPU Rear left turn signal lamp Hazard Lamp Switch Left turn signal lamp switch Turn signal lamp sound relay Cluster Right turn signal lamp switch Indicator and hazard lamp control through switch operation is processed by the SJB alone Indicator and hazard lamp switch signals are input directly in the SJB The SJB activates lamps by operating the indicator sound relay and IPS At the same time, data is sent to the cluster through the CAN line to light up the indicators The indicators can be switched on when the ignition is both on or off Hazard lamp blinking by the RKE is collectively triggered by the BCM and SJB When the BCM receives RKE remote control data, a hazard lamp activation command is given to the SJB through CAN communication 17 3) Tail Lamp Auto Off Control SJB Driver Side Door Switch Tail Lamp Switch IPS Control CPU Switch Signal Tail Lamp OFF BCM Tail Lamp OFF The tail lamp automatically turns off when removing the key and opening the door Tail lamp "on" signals are detected by the SJB Turning off the ignition and opening the driver side door sends a "driver door open" signal to the SJB The SJB sends door switch data and tail lamp switch data to the BCM The BCM sends a "tail lamp off" signal to the SJB and the SJB turns off the tail lamps 4) Head Lamp Escort Control SJB Door switches (four total) Hood Switch Trunk Switch CPU Switch Signal IPS Control Head lamp OFF BCM Head Lamp OFF H/Lamp Low Passive lock Auto light SMK The head lamp escort function is only enabled when the escort function is switched on in the USM With the head lamp escort function, turning off the ignition while the head lamps are on keeps them on for about 20 minutes (can vary by vehicle model) before switching off Head lamp "on" signals are detected by the BCM Switching off the ignition makes the BCM give the "head lamps off" command to the SJB after 20 minutes Closing all doors after switching off the ignition sends a door switch signal to the SJB If the remote control lock or passive lock switch is pressed, the BCM detects the signal and activates the anti-theft mode When this happens, a "head lamps off" command is given to the SJB after 30 seconds Pressing the remote control lock button twice while in anti-theft mode sends a signal to the BCM, which immediately sends a "head lamps off" command to the SJB 18 2.4 Door Lock/Unlock Control 1) Central Door Lock/Unlock Control(RKE, power door lock switch) SJB Power door lock switch Switch Signal IPS Control CPU All-door Lock/Unlock BCM Door lock output command Central door lock/unlock control is executed by the BCM and SJB When the user presses the power door lock switch, a signal is sent to the SJB The SJB then sends a switch signal to the BCM through CAN communication If the door lock/unlock requirements are met, the BCM sends a "lock/unlock" command to the SJB After receiving the BCM's command, the SJB activates the IPS to control the door lock relay RKE door lock/unlock signals are received by the BCM The BCM sends a door lock/unlock command to the SJB, and the SJB activates the IPS 2) Speed-sensitive Door Lock SJB Vehicle Speed BCM Door lock output command IPS Control CPU All-door Lock/Unlock Enabling speed-sensitive door lock control in the USM enables automatic central door lock control at the set speed Speed signals are sent to the gateway (cluster or BCM) through CCAN, and passed on to the BCM If the vehicle exceeds the set speed, a door-lock command is sent to the SJB, which then locks all doors 3) Impact-sensing Door Unlock Control SJB A C U Crash output B C M Door lock output command IPS Control CPU All-door Lock/Unlock In the event of airbag deployment upon impact, the ACU sends a crash signal to the BCM The BCM gives an "all-door-unlock" command to the SJB to let everyone out of the vehicle The SJB unlocks all doors 19 2.5 Miscellaneous Controls 1) Heating Wire Timer Control SJB Glass heating wire signal Relay output/OFF Alternator “L” signal BCM Relay Control CPU Defogger Output Pressing the heating wire switch while the ignition is on, i.e when charge voltage is being output from the generator's L terminal, activates the heating wire for approximately 20 minutes before switching off automatically When the heating wire switch in the FATC is enabled, the BCM detects the switch signal If the heating wire activation requirements are met, the BCM give an "activate heating wire relay" command to the SJB The SJB activates the relay to supply power to the heating wire 20 minutes after heating wire operation, an "output off" command is sent to the SJB to switch off the heating wire The SJB deactivates the relay to cut off heating wire output 2) Anti-theft Mode SJB Door switches (four total) Hood Switch Trunk Switch All-door lock IPS Control CPU Switch Signal IPS Control BCM Hazard lamp control All-door lock Security Lamp Passive lock SMK All doors must be closed and locked and the trunk and hood closed for the anti-theft alarm to activate A door switch signal, hood switch signal and trunk switch signal are sent to the SJB, which passes the signals on to the BCM through CAN communication If the BCM receives a remote control lock signal or passive lock signal in this state, an "all-door-lock" command is sent to the SJB (refer to the Door Lock Control section) After all doors are locked the BCM sends a hazard lamp output command to the smart junction box and, at the same time, activates the security lamps After entering the anti-theft mode, the burglar alarm activates and ignition is disabled if any of the doors, hood and trunk is opened 20 Service Procedure 1) Key Current Data < BCM Current Data > The GDS supports current data required by the BCM and SJB Selecting the initial BCM item allows the selection of BCM or SJB for current data viewing The current data of the BCM and SJB displays the switch signals and output signals received by each module Correct switch input and module output signals for a particular function can be verified by viewing the current data 21 2) Actuation Test The BCM and SJB can perform an actuation test on the relays they each control Each relay can be activated through the activation test and output can be verified as normal 3) User Option In User Options, some convenience functions controlled by the BCM and SJB can be turn on or off to suit the user This function is similar to that of USM on the cluster The convenience functions that can be enabled/disabled include Auto Door Lock, Auto Door Unlock, Welcome Light and Headlamp Escort 22 4) Transmitter Register For remote keyless entry, transmitter code saving is required after a key or BCM replacement This procedure enters key data in the BCM, and is not the same as a key registration in the immobilizer system (For smart key systems, only a smart key registration is required.) Key Registration Process 23 ... relays When the transistor switches on, the relays become magnetized and lamps operate If output is executed by a module other than the one that detected the switch signal, the "switch on" signal is... Control CPU All-door Lock/Unlock BCM Door lock output command Central door lock/unlock control is executed by the BCM and SJB When the user presses the power door lock switch, a signal is sent to