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Home >> Hyundai >> 2020 >> Elantra Eco >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Idle Stop & Go (ISG) System - 1.4L >> Schematic Diagrams >> Operation Condition For The ISG Function >> Operation Condition for the ISG function

Operation Condition for the ISG function

  1. Auto stop or Auto start condition 
    • If all of the below condition are satisfied
    Component State Remark
    ISG OFF Switch OFF ISG OFF switch indicator lamp ->OFF
    Air conditioning system Ambient temperature is between -2° - 35°C (28.4° - 95°F)  
    Engine Coolant Temperature Over 30°C (86°F)  
    Brake vacuum Below -35 kPa  
    Drive door, Seat belt, Hood Closed  
    EMS state (TPS/CKP/CMP/WTS/Vehicle speed signal) satisfy DPF Regeneration prohibited
    A/C System satisfy  
    Battery sensor [SOC: Over 78%, Temperature: 2°- 55°C (35.6° - 131°F)] satisfy  
    ISG related part error Does not occur  
    Vehicle speed Entry the below 0 kph after Over 8 kph Prohibition the ISG System before 8 kph
    Accelerator pedal OFF Engine auto stop condition
    Brake switch ON Engine auto stop condition
    OFF Engine auto stop condition
    Gear state N (Neutal)/D Engine auto stop condition
    R/1/2 Engine auto stop condition
    NOTE:
    • In congested areas, if the driver wishes to stop the vehicle and change lever from D→N, the ignition will turn OFF.
  2. Restriction conditions Auto stop or Auto start 
    • If one of the following conditions is met, the ISG system will not operate properly.
    Component Conditions Remark
    ISG OFF switch ON ISG OFF switch indicator state
    EMS State (TPS/CKP/CMP/WTS/Vehicle speed signal etc.) Dissatisfaction DPF Regeneration prohibited
    Drive door, Seat belt, hood state Open  
    Brake vacuum Over -35 kPa  
    A/C State Dissatisfaction  
    Battery sensor (SOC: Over 78%, Temperature: 2 - 60°C) Dissatisfaction  
    ISG system error Occur  
    Steering wheel Greater the angle  
    A/C System A/C switch ON, FATC over 6, MTC over 3  
    Defrost Defrost switch ON  
    etc Downhill, Rapid ascents  
    Operate the SPAS  
  3. Forced re-start conditions (If any of the below condition is not satisfied) 
    Component Conditions Remark
    Conditions for safety Low pressure for braking system Over -35 kpa
    Low battery voltage Continue the electrical load during the 3 min
    Active defroster of front glass  
    When inertial speed reach 1.5 km/hour with (down hill)  
    Open the door or unfasten driver's seat belt Brake Pedal Pressed
    Open the hood, ignition switch starting  
    Elapsed much of stop time After 300 sec.
    Stop the vehicle at rapid ramp  
    Conditions for convenience A/C ON, FATC over 6, MTC over 3 or dissatisfaction HVAC performance  
    Active 'ISG OFF' button  
  4. Restriction conditions for Auto-Stop operation 
Conditions State Remark
Drive door, seat belt, hood state (Brake OFF state) Open Starting is possible to "ignition switch or button start key" (Only)
CAN error (TCU, FATC/Cluster) Occur
EMS state (TPS/CKP/CMP/WTS/Vehicle speed signal) Dissatisfaction
NOTE:
  • If error occurred in the idle stop status, it is possible to start the engine by the key only.
CAUTION:
  • 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.
CAUTION: ISG system deactivation by fault.
  • Fault in communication line (LIN/CAN)

    Fault Electric oil pump

    Fault ESP 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.
WARNING:
  • 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.