Hyundai Sonata LF Quiz
Body Electrical System

Description and Operation

In this manual: Body Electrical System
General Information — 9Engine Mechanical System — 90Engine Electrical System — 58Emission Control System — 24Engine Control System/Fuel System — 114Drive Shaft and Axle — 15Suspension System — 35Steering — 19Restraints — 50Brake System — 54Body (Interior and Exterior) — 213Body Electrical System — 241Heating, Ventilation, and Air Conditioning — 56DCT (Dual Clutch Transmission) System — 52
~12min read

Description

Body Control Module (BCM) Function
No Item Description
1 Washer-linked wiper
  • If the washer switch is pressed for 0.06~0.2 seconds with the vehicle mode in IGN2, the wiper relay turns on 0.3 ± 0.1 seconds after the washer turns on, and then the wiper relay turns off 0.7 ± 0.1 seconds later.
  • If the washer switch is pressed for more than 0.2 seconds with the vehicle mode in IGN2, the wiper relay turns on 0.3 ± 0.1 seconds after the washer turns on, and then the wiper relay turns off 2.5~3.8 seconds (wiper operates 2-3 times) after the washer turns off.
2 MIST-linked wiper
  • If the wiper mist switch is pressed for 0.7 seconds with the vehicle mode in IGN2, the wiper relay turns on, and then turns off 0.7 seconds later.
  • If the wiper fog switch is pressed for more than 0.7 seconds in vehicle mode with IGN2 on, the wiper relay turns on, and then turns off 0.7 seconds after the wiper fog switch is turned off.
3 Variable INT wiper
  • If the INT wiper switch is turned on with the vehicle mode in IGN2, the INT wiper operates intermittently (10 ~ 2.2 s) according to the INT volume setting.
4 Rear window heater timer
  • If the heater switch is turned on with the vehicle mode in IGN ON and the generator running, the heater relay turns on for 20 minutes.
  • If the heater switch is pressed again, or if the generator mode is turned off while the heater is on, the heater relay turns off.
5 Shift Interlock
  • If the brake switch is on in vehicle mode with IGN1 on and the shift lever in P, the ATM solenoid turns on to unlock the shift lever.
6 Trunk release
  • The trunk release relay turns on for 0.2±0.02 seconds when the trunk TX signal is received.
  • If the trunk opener switch is turned on when all doors are unlocked, the trunk release relay turns on for 0.2±0.02 seconds. (However, the trunk opener switch is ignored in ARMWAIT, ARM, REARM or ALARM modes.)
  • If the interior trunk open switch is on, the trunk open relay turns on for 0.2±0.02 seconds. (However, the trunk open relay does NOT turn on if the vehicle speed exceeds 5 km/h, or if the vehicle is in ARMWAIT, ARM, REARM, or ALARM mode.)
7 Power window timer
  • The power window indicator relay turns on when the vehicle mode switches to IGN ON.
  • When the vehicle mode switches from IGN ON to OFF, the power window relay turns on for 30 seconds.
  • If a door is opened during the 30-second period of the power window relay being on, the power window relay turns off immediately.
  • If a door is open and the vehicle mode switches from IGN ON to OFF, the power window relay turns off immediately.
8 KEY IN Warning
  • If the driver door is opened with the KEY IN, the buzzer sounds continuously at 1-second intervals.
  • The buzzer turns off if KEY OUT or the door is closed while the buzzer is sounding.
9 Parking brake warning
  • If the vehicle speed exceeds 5 km/h while the ignition mode is IGN1 and the parking brake is applied, the buzzer sounds until the parking brake is released. (The buzzer activates 0.6 seconds after the parking brake is applied and deactivates 0.4 seconds after, repeating at 1-second intervals until the parking brake is released.)
10 Room Lamp Fade-Out
  • If a door is opened with the vehicle mode in IGN OFF, the room lamp turns on. If the door is then closed, the room lamp remains ON for 30 seconds and then turns off. (Dimmer: 2 ± 0.2 sec.)
  • If the door remains open, the room lamp remains on for 20 minutes and then turns off. (Dimmer: 2 ± 0.2 sec.)
11 KEY HOLE Illumination
  • Key Hole Illumination Lamp: The lamp turns on when the door is opened while the vehicle mode is in IGN1 OFF, and the key hole illumination lamp is on. It turns off 30 seconds after the door is closed.
  • If the vehicle mode is switched to IGN1 ON while the key hole illumination lamp is on, the lamp turns off immediately.
  • If the vehicle mode is switched to ARMWAIT while the key hole illumination lamp is on, the lamp turns off immediately.
12 Tail Lamp Auto Off
  • If the tail switch is changed from OFF to ON, the tail lamp relay is turned on.
  • If the tail switch is OFF, the tail lamp relay is turned off.
  • If the KEY IN switch is OFF and the tail switch is ON, and the driver's door is opened while the KEY IN switch is ON and the tail switch is ON, the tail lamp relay is turned off. (Auto OFF)
  • If the KEY IN switch is turned ON after Auto OFF, the relay is turned on. The tail lamp relay does not turn on even if the driver's side door is opened and closed.
13 Headlamp Follow-Me
  • If the vehicle mode is changed from IGN1 to IGN1 OFF and the headlamp is turned on by the headlamp switch or auto light, the headlamp remains on.
  • The headlamp turns off under any of the following conditions.15 seconds after the driver's door is opened and closed.The headlamp or auto light is not turned on.If the driver's door remains open for more than 5 minutes.20 minutes after the vehicle mode is changed from IGN1 ON to IGN OFF.If the TX Lock signal is received 2 times while the headlamps are on.
14 Headlamp LOW/HIGH Beam
  • If the low beam headlamps are on with the headlamp switch or auto light function on, and the high beam switch is turned on (momentary), the high beam headlamps turn on.
  • The high beam headlamps can only be turned off by the headlamp switch.
15 Low Beam Headlamp
  • The high beam headlamps are activated only when the headlamp switch is on and the vehicle mode is in IGN2 ON.
  • The switch is used to turn off the high beam headlamps when they are on.
16 Front Fog Lamp
  • If the front fog lamp is turned on while the tail lamp is on, the front fog lamp turns on.
  • If the front fog lamp switch is turned off while the front fog lamp is on, the lamp turns off.
  • If the low beam headlamps are turned on while the front fog lamps are on, the front fog lamps also turn on.
  • If the front fog lamp switch is turned off while the front fog lamp is on, the lamp turns off.
17 Automatic Light Control
  • If the auto light sensor detects a light-on condition, the lights turn on after 2.5 seconds.
  • If the sensor detects a light-off condition, the lights turn off after 2.5 seconds.
  • If the sensor detects the tail lamp on condition, only the tail lamp turns on. If the sensor detects the headlamp on condition, the tail lamp and headlamp turn on.
  • When the headlamp is turned on, the tail lamp and headlamp turn on regardless of the on/off state of the tail switch.
18 Daytime Running Lamps (DRL)
  • The DRL lamp turns on when the engine is started.
  • The DRL lamp turns off when the low beam headlamps or front fog lamps are turned on.
19 Headlamp Welcome
  • If the vehicle mode is switched to KEY OFF, all doors are closed and locked, and the headlamp is on (headlamp switch or AUTO switch + nighttime), then the RKE unlock is activated and the headlamp turns on for 15 seconds.
20 Tail Lamp Linkage
  • When the vehicle mode is switched to ACC ON, the auto light sensor reflects the light level.
  • If the auto light ambient light level is in the tail lamp ON state for more than 2.5 seconds, the ON signal is sent.
  • If the auto light ambient light level is in the tail lamp OFF state for more than 2.5 seconds, the OFF signal is sent.
21 DPAS
  • If the shift lever is moved to the R position while the vehicle mode is IGN1 ON, the buzzer sounds after 0.5 seconds.
  • The warning level is displayed in the cluster, and the buzzer sounds according to the warning condition.
22 Horn Chirp Response
  • If all doors are closed and the vehicle enters ARM mode with TX Lock control, then a TX Lock signal is received within 4 seconds to maintain ARM mode, the horn chirp and hazard lamps are activated.
  • If ARM mode is cancelled within 4 seconds, the horn chirp and hazard lamps do not activate.
  • The horn chirp and hazard lamps activate if another registered TX Lock signal is received within 4 seconds.
23 Normal/ARMWAIT/Relock Mode
  • If the TX lock signal is received with the KEY IN switch removed from the cylinder and all doors closed, the all-door lock signal is output. When all door lock switches are locked, the hazard lamp flashes once and the vehicle enters SECURITY mode after the ARMWAIT time (30 sec.) has elapsed.
  • If the TX lock signal is received while any door, the hood, or the trunk is open, only the lock signal is output. The hazard lamp does not flash and the vehicle does not enter security mode.
  • If none of the doors is opened or KEY IN is not detected within 30 seconds after receiving the TX unlock signal, the vehicle returns to security mode.
24 Security Indicator Control
  • If the vehicle is in ARMWAIT mode when KEY OUT, the indicator remains on. The indicator flashes at intervals when the vehicle is in any mode other than ARMWAIT. (Flashing interval: 2 sec. OFF, 0.3 sec. ON)
25 Alarm Condition
  • If an alarm trigger condition is detected, the start inhibit is activated to prevent engine start and the alarm is activated.
  • The alarm sounds 2 times (27 sec. ON, 10 sec. OFF).
26 DISARM/Alarm Deactivation Condition
  • If the TX UNLOCK/LOCK switch signal is received, the unlock/lock signal is output for 0.5 seconds, and START INHIBIT is deactivated.
  • If the KEY IN switch = ON, the IGN1 switch = ON and the IGN2 switch = ON & generator = ON is maintained for 30 seconds, then the START lock is released and the vehicle mode switches to DISARM.
27 RESET
  • If the battery is disconnected while the alarm is being armed and then reconnected, the alarm is also armed again.
  • If the battery is disconnected while the vehicle is in ARM mode and then reconnected, the vehicle remains in ARM mode.
28 PANIC
  • If a TX_Panic signal is received, the panic alarm activates, and the siren and hazard lamps operate for 27±2 sec.
  • If a signal is received while the panic alarm is active, the panic alarm is deactivated.
  • If the arming conditions are met while the alarm is active, the vehicle enters ARM mode.
29 MTS Function
  • If an Unlock signal is received from the MTS, all doors unlock.
  • If a Lock signal is received from the MTS, all doors lock.
  • If a "Remote Engine Start" signal is received, a "Remote Engine Start" command is sent to the SMK.
  • If a "Panic and Horn" signal is received, the hazard lamps and horn activate.
30 Central Door Lock/Unlock
  • If the driver/passenger door lock/unlock KEY switch is turned on for 3 seconds, the lock/unlock signal is output to all doors for 0.5 seconds.
  • If the TX lock/unlock signal is received, the lock/unlock signal is output to all doors for 0.5 seconds.
  • If the driver door lock switch (power window) is in the lock/unlock position, the lock/unlock signal is output to all doors for 0.5 seconds.
31 Auto Door Lock
  • If the vehicle is in IGN1 ON mode, the alternator is on, and the vehicle speed exceeds 15 km/h, all doors lock within 1.5 seconds. (However, if all doors are already locked, or in case of failure of all doors, the all-door lock function is not performed.)
  • If any door is unlocked after locking under the above condition, the lock command is performed 3 times (at 1 second intervals). A door that is not locked during the 3 attempts is ignored.
  • The auto door lock function does not activate in the event of unlocking due to a collision.
32 Automatic Door Unlock
  • If KEY OFF follows KEY IN, all doors are unlocked. (However, if all doors are already unlocked, the unlock command is not performed.)
33 Driver Door Unlock Switch Synchronized Auto Unlock
  • If all doors are closed and the driver door unlock switch is changed from locked to unlocked, all door unlock signals are output once for 0.25 seconds.
34 IGNITION KEY REMINDER This function is not activated if the vehicle speed exceeds 3 km/h.
  • If the KEY IGNITION is ON, the driver door switch = OPEN, and the driver door unlock status becomes locked, all door unlocks are performed for 1 second after a 0.5-second delay.
  • KEY IGNITION ON, the passenger door switch = OPEN, and the passenger door unlock status becomes locked, all door unlocks are performed for 1 second after a 0.5-second delay.
  • If the driver door switch is closed within 0.5 seconds, the driver door unlock state changes from UNLOCK to LOCK. When the vehicle is in IGN KEY ON mode, all doors are unlocked only once for 1 second.
  • If the unlock condition is met, unlocking is performed even if the condition is not maintained for 0.5 seconds.
35 Passive Key Reminder
  • This function is not activated if the vehicle speed exceeds 3 km/h.
  • If a KEY Reminder signal is received from the SMK, all door unlock commands are output for 1 second.
  • If the door remains locked even though the unlock command is output for 1 second as described above, unlocking is attempted up to 3 times (excluding the 1st output) (interval 1 s: 0.5 s on/off).
36 Emergency Door Unlock
  • The unlock is performed each time an ACU signal is received while the IGN switch is ON. The unlock output continues for the set time, even if the vehicle mode changes from IGN KEY ON to OFF.
  • If the driver/assistant/rear door lock switch is switched from unlock to lock after unlocking is performed, the unlock command is performed again for 5 seconds.
  • The auto door lock function does not activate in the event of unlocking due to a collision.
37 HBA (High Beam Assist)
  • If the high beam switch is turned on in AUTO night mode, HBA mode is activated.
  • In HBA mode, when an oncoming vehicle or a preceding vehicle is detected (input signal from LDWS), the headlamp high beams are turned off.
  • If no oncoming or preceding vehicle is detected, the headlamp high beams are turned on automatically.

Communication Network Diagram
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
LDWS Lane Departure Warning 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
SPAS Smart Parking Assist System (SPAS)
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

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A quick Hyundai Sonata LF quiz: every answer comes with an explanation and a link to the manual page.