Hyundai Tucson: Emission control system

Hyundai Tucson - Fourth generation (NX4) - (2020-2023) - Owner's Manual / Maintenance / Emission control system

The emission control system of your vehicle is covered by a written limited warranty. Please see the warranty information contained in the Service Passport in your vehicle.

Your vehicle is equipped with an emission control system to meet all applicable emission regulations. There are three emission control systems, as follows.

  1. Crankcase emission control system
  2. Evaporative emission control system
  3. Exhaust emission control system

In order to ensure the proper function of the emission control systems, it is recommended that you have your vehicle inspected and maintained by an authorized HYUNDAI dealer in accordance with the maintenance schedule in this manual.


For the Inspection and Maintenance Test (with Electronic Stability Control (ESC) system)

  • To prevent the vehicle from misfiring during dynamometer testing, turn the Electronic Stability Control (ESC) system off by pressing the ESC switch (ESC OFF light illuminated).
  • After dynamometer testing is completed, turn the ESC system back on by pressing the ESC switch again.

1. Crankcase emission control system

The positive crankcase ventilation system is employed to prevent air pollution caused by blow-by gases being emitted from the crankcase. This system supplies fresh filtered air to the crankcase through the air intake hose. Inside the crankcase, the fresh air mixes with blow-by gases, which then pass through the PCV valve into the induction system.

2. Evaporative emission control system

The Evaporative Emission Control System is designed to prevent fuel vapors from escaping into the atmosphere.


Fuel vapors generated inside the fuel tank are absorbed and stored in the onboard canister. When the engine is running, the fuel vapors absorbed in the canister are drawn into the surge tank through the purge control solenoid valve.

Purge Control Solenoid Valve (PCSV)

The purge control solenoid valve is controlled by the Engine Control Module (ECM); when the engine coolant temperature is low during idling, the PCSV closes so that evaporated fuel is not taken into the engine. After the engine warms-up during ordinary driving, the PCSV opens to introduce evaporated fuel to the engine.

3. Exhaust emission control system

The Exhaust Emission Control System is a highly effective system which controls exhaust emissions while maintaining good vehicle performance.

When the engine starts or fails to start, excessive attempts to restart the engine may cause damage to the emission system.

Engine exhaust (carbon monoxide) precautions

  • Carbon monoxide can be present with other exhaust fumes. If you smell exhaust fumes of any kind in your vehicle, drive with all the windows fully open. Have your vehicle checked and repaired immediately.


Engine exhaust gases contain carbon monoxide (CO). Though colorless and odorless, it is dangerous and could be lethal if inhaled. Follow the instructions on this page to avoid CO poisoning.



Engine exhaust and a wide variety of automobile components and parts, including components found in the interior furnishings in a vehicle, contain or emit chemicals known to the State of California to cause cancer and birth defects and reproductive harm.

In addition, certain fluids contained in vehicles and certain products of component wear contain or emit chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

  • Do not operate the engine in confined or closed areas (such as garages) any more than what is necessary to move the vehicle in or out of the area.
  • When the vehicle is stopped in an open area for more than a short time with the engine running, adjust the ventilation system (as needed) to draw outside air into the vehicle.
  • Never sit in a parked or stopped vehicle for any extended time with the engine running.
  • When the engine stalls or fails to start, excessive attempts to restart the engine may cause damage to the emission control system.

Operating precautions for catalytic converters (if equipped)


The exhaust system and catalytic converter are very hot during and immediately after the engine has been running. To avoid SERIOUS INJURY or DEATH:

  • Do not park, idle, or drive the vehicle over or near flammable objects, such as grass, vegetation, paper, leaves, etc. A hot exhaust system can ignite flammable items under your vehicle.
  • Keep away from the exhaust system and catalytic converter or you may get burned.

    Also, do not remove the heat sink around the exhaust system, do not seal the bottom of the vehicle, and do not coat the vehicle for corrosion control. It may present a fire risk under certain conditions.

Your vehicle is equipped with a catalytic converter emission control device.

To prevent damage to the catalytic converter and to your vehicle, take the following precautions:

  • Use only UNLEADED FUEL for gasoline engines.
  • Do not operate the vehicle when there are signs of engine malfunction, such as misfire or a noticeable loss of performance.
  • Do not misuse or abuse the engine.

    Examples of misuse are coasting with the engine off and descending steep grades in gear with the engine off.

  • Do not operate the engine at high idle speed for extended periods (5 minutes or more).
  • Do not modify or tamper with any part of the engine or emission control system. We recommend that all inspections and adjustments are made by an authorized HYUNDAI dealer.
  • Avoid driving with an extremely low fuel level.

    Running out of fuel could cause the engine to misfire, damaging the catalytic converter.

Gasoline Particulate Filter (GPF) (if equipped)

Gasoline Particulate Filter (GPF) system removes the soot in the exhaust gas.

The GPF system automatically burns (or oxidizes) the accumulated soot in accordance with driving situations, unlike a disposable air filter.

In other words, the accumulated soot is automatically purged out by the engine control system and by the high exhaustgas temperature at normal/ high driving speeds. However, when the vehicle is continually driven at repeated short distances or driven at low speed for a long time, the accumulated soot may not be automatically removed because of low exhaust gas temperature. In this case, the accumulated soot may reach a certain amount regardless of the soot oxidization process, then the GPF lamp ( ) will illuminate.

The Gasoline Particulate Filter (GPF) lamp stops illuminating, when the driving speed exceeds 50 mph (80 km/h) with engine RPM 1,500 ~ 4,000 and the gear in the 3rd position or above for approximately 30 minutes.

When the GPF lamp starts to blink or the warning message "Check exhaust system" pops up even though the vehicle was driven as mentioned above, we recommend that you have the GPF system checked by an authorized HYUNDAI dealer.

With GPF lamp blinking for an extended period of time, it may damage the GPF system and lower the fuel economy.


We recommend you to use only the regulated gasoline fuels, when your vehicle is equipped with the GPF system.

When you use other gasoline fuels which contain unspecified additives, they may damage the GPF system and cause exhaust emission problems.

California perchlorate notice

Notice to California Vehicle Dismantlers: Perchlorate containing materials, such as air bag inflators, seatbelt pretensioners and keyless remote entry batteries, must be disposed of according to Title 22 California Code of Regulations Section 67384.10 (a).


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