Hyundai Tucson: Idle Stop and Go (ISG)
Idle Stop and Go helps reduce fuel consumption by automatically shutting down the engine, when the vehicle is at a standstill (i.e. red stop light, stop sign, and traffic jam) subject to certain prerequisite conditions being satisfied as listed below.
The engine is automatically started upon satisfying the starting conditions.
ISG system is always active, when the engine is running.
When the engine is automatically started by ISG system, warning lights (i.e. ABS, ESC, ESC OFF, EPS, and parking brake warning light) may illuminate for a few seconds due to low battery voltage.
However, it does not indicate a malfunction with ISG system.
ISG system operation
Prerequisite for activation
ISG system operates in the following situations.
- The driver's seatbelt is fastened
- The driver's door and hood are closed
- The brake vacuum pressure is adequate
- The battery sensor is activated and the battery is sufficiently charged
- Outside temperature is not too low or too high
- The vehicle is driven over a constant speed and stops
- The climate control system satisfies the conditions
- The vehicle is sufficiently warmed up
- ISG related parts are working properly
- The incline is gradual
- The steering wheel is turned less than 180 degrees and then the vehicle stops
If the ISG light (white) is turned on on the instrument cluster and does not meet the ISG system operating conditions, the ISG system is not activated.
When the ISG light (yellow) is on while the ISG system meets operating conditions, we recommend that the system be inspected by an authorized HYUNDAI dealer.
When ISG is on the engine will be stopped automatically when both of the following occurs:
- Vehicle speed decreases to 0 mph (0 km/h) full stop condition.
- Brake pedal is depressed and gear is in D (Drive) or N (Neutral).
The Auto Stop ( ) indicator illuminates in green on the instrument cluster, when the engine stops.
Idle stop cannot reoccur again until the vehicle speed goes above 3 mph (5 km/h) and then returns again to the automatic stop conditions as previously mentioned.
In the Auto Stop mode, if the engine hood is opened, ISG system will be deactivated.
When the system is deactivated, the ISG off button indicator will illuminate and a message 'Auto Stop is off. Shift to P or N to start engine manually' appears on the cluster LCD display with a warning sound.
If this occurs, depress the brake pedal and restart the engine manually.
When the engine stops automatically by ISG, the engine will restart if one of the following is done.
- Release the brake pedal.
- When Auto Hold is activated, take your foot off the brake pedal and then depress the accelerator pedal.
- While depressing the brake pedal, shift the gear from N (Neutral) or D (Drive) to R (Reverse) or P (Park).
- While depressing the brake pedal, shift the gear from N (Neutral) to D (Drive).
The Auto Stop ( ) indicator goes to white on the instrument cluster, when the engine is restarted.
LCD display messages
The messages are displayed on the instrument cluster to help use ISG system.
Auto Stop is Off. Shift to P or N to start engine
When the system is deactivated, the ISG off button indicator will illuminate and a message will appear on the cluster LCD display with a warning sound in the following situations.
- When the engine hood is opened.
- When ISG system is not working normally.
If this occurs, depress the brake pedal and restart the engine manually. For your safety, restart the vehicle in the P (Park) position.
Press brake pedal before driving on / Press brake pedal for Auto Start
When the gear is shifted from N (Neutral) to R (Reverse), D (Drive) or Manual shift mode without the brake pedal depressed, a message will appear on the cluster LCD display. To activate auto start, depress the brake pedal.
AUTO STOP elapsed time
AUTO STOP display shows the elapsed time of engine stop by the Idle Stop and Go system.
You may check AUTO STOP elapsed time in the Utility view on the instrument cluster.
Refer to "View Modes" section in chapter 4.
ISG system off
Press the ISG OFF button to turn off ISG system. The ISG OFF button indicator will illuminate. To use the system, press the ISG OFF button again.
Forced to restart engine
The engine is automatically restarted in the following situations.
- The brake vacuum pressure is low
- The engine has stopped for about 5 minutes
- The air conditioning is ON with the fan speed set to a certain high level
- The front defroster is ON
- The battery is weak
- The cooling and heating performance of the climate control system is unsatisfactory
- The vehicle is shifted to P (Park) or R (Reverse) when Auto Hold is activated
- The door is opened or the seatbelt is unfastened when Auto Hold is activated
- The EPB switch is pressed when Auto Hold is activated
The Auto Stop ( ) indicator blinks in green for 5 seconds on the instrument cluster when the engine is restarted.
When the engine is in Idle Stop mode, the engine may restart without the driver taking any action. Before leaving the vehicle or working on the engine compartment, turn off the engine by pressing the ENGINE START/STOP button to the OFF position.
ISG system may not operate when there is a malfunction with the ISG sensors or ISG system.
The following will occur, when there is a malfunction with the ISG system:
- The Auto Stop ( ) indicator will illuminate in yellow on the instrument cluster.
- The light on the ISG OFF button will illuminate.
We recommend that you contact an authorized HYUNDAI dealer.
If the AGM battery is reconnected or replaced, ISG system will not operate immediately. If you want to use the system, the battery sensor needs to be calibrated for approximately 4 hours with the engine off.
After calibration, turn the engine on and off 2 or 3 times.
- Hyundai Tucson - Fourth generation (NX4) - (2020-2023) - Owner's Manual
- Hyundai Tucson - Fourth generation (NX4) - (2020-2023) - Workshop Manual