Hyundai Elantra MD/UD: Operation Condition for the ISG function - Description and Operation - ISG (Idle Stop & Go) System - Fuel System - Hyundai Elantra MD 2010-2015 Service manualHyundai Elantra MD/UD: Operation Condition for the ISG function

1. Auto stop or Auto start condition (If all of the below condition are satisfied)
Driving conditions
ISG OFF Switch
Lever position
D or N range
Prohibit operation on gear ‘P, R’
Brake pedal
Auto Stop
Auto Start
Vehicle speed
Vehicle speed = 0 Mph
After driving higher than 8kph (5 Mph)
Air conditioning
Ambient temperature is between
 -2 ~ 35 °C (28.4 ~ 95 °F)
Engine Coolant Temperature (ECT)
Over 78 °C (172.4 °F)
Brake Pressure
Below -35kpa
Battery conditions
Over 77%
To protect Battery
2 ~ 55 °C (35.6 ~ 131 °F)
Steering wheel
Operating angle
Below 180°
Parking condition
Up hill <12%, Down hill < 8%
ISG related part error
Sensor Error
Brake Booster Pressure Sensor
Brake Master Cylinder Pressure  
Sensor, Brake Pedal Sensor,
APS, Battery Sensor
Related System Error
TM Electronic Auxiliary Pump
ESC System Defect Mode
CAN Communication Error
Engine Limp Home Mode

2. Forced re-start conditions (If any of the below condition is not satisfied)
Conditions for safety
Low pressure for braking system
Over -35kpa
Low battery voltage
Below 12.1V for 180 sec
Active defroster of front glass
When inertial speed reach 1Mph with  (down hill)
Over 1Mph (Kph)
Inertial Speed
Open the door or unfasten driver’s seat belt
Brake Pedal Pressed
Elapsed much of stop time
On the steep slope way
Conditions for convenience
Turn on the air-conditioner or max blower speed or bad performance of air conditioning and heating
Active ‘ISG OFF’ button
Sign of forced auto re-start
Blinking of lamp for 5 second and indicating on cluster

3. Restriction conditions for Auto-Stop operation
※ To protect system and safety auto-stop system is restricted below the conditions
Large steering angle when car is stop
Low brake operating pressure
Turn on the air conditioner with max blower
When battery Condition is poor (low SOC)
Active defroster of front or rear glass
Unfasten driver’s seat belt or open the door and hood
On the steep slope way
With ISG system errors,  and other diagnosis

4. Restriction condition for auto Re-Start operation
Open hood (have to restart by key for repairman’s safety )

5. Restriction condition for OBD Check & Emission control
Auto Stop system
will be limited
During Canister purge monitoring
During OBD check
To restrict continuous Cranking
 (for Emission Control)
Start Motor can operate for two seconds at the longest (just once)

The ISG system is strongly networked with the power management. In the event of battery replacement, disconnection of the battery terminal or after changing the engine management system, the reference data regarding the battery charge state and battery condition can be lost.
They are only available again a closed-circuit current measurement of approximate 4 hours in which the vehicle may not be wakened. In this time, the ISG system is inactive.
ISG system deactivation by fault.
Fault in communication line (LIN/CAN)
Fault Electric oil pump
Fault ESC System
Fault Limp home mode
Fault brake booster vacuum pressure sensor
Fault Brake master cylinder pressure sensor
Fault Brake pedal switch
Fault Battery sensor
When the ISG related sensors or system error occurs, the ISG OFF switch lights up. Especially when the battery sensor is replaced or reinstalled, the vehicle must be placed in the ignition switch OFF for about 4 hours for recalibration.
The ISG function is operated about 4 hours later normally. But in the case of first 25 times, the ISG function can be operated regardless of recalibration.
When the engine is in Idle stop mode, it's possible to restart the engine without the driver taking any action.
Before leaving the car or doing anything in the engine room area, stop the engine by turning the ignition key to the LOCK position or removing it.

1. Vehicle moving. 2. The transmission lever position is D-range. The brake pedal is released. 3. The ...

Components and Components Location
Components Location 1. Battery sensor 2. Brake Booster Vacuum Pressure Sensor (BBVPS) 3. AGM battery 4. DC/ DC Converter (LDC) [200W] 5. DC/ DC Converter (LDC) [400W] ...