Check your tires, including the spare tire, once a month or more.
How to check
Use a good quality tire pressure gauge to check tire pressure. You can not tell if your tires are properly inflated simply by looking at them. Radial tires may look properly inflated when they are under-inflated.
Remove the valve cap from the tire valve stem. Press the tire gauge firmly onto the valve to get a pressure measurement. If the cold tire inflation pressure matches the recommended pressure on the tire label located on the driver's side center pillar or in this manual. No further adjustment is necessary. If the pressure is low, add air until you reach the recommended pressure. Make sure to put the valve caps back on the valve stems. Without the valve cap, dirt or moisture could get into the valve core and cause air leakage. If a valve cap is missing, install a new one as soon as possible.
If you overfill the tire, release air by pushing on the metal stem in the center of the tire valve. Recheck the tire pressure with the tire gauge. Be sure to put the valve caps back on the valve stems. Without the valve cap, dirt or moisture could get into the valve core and cause air leakage. If a valve cap is missing, install a new one as soon as possible.
A cold tire means the vehicle has been sitting for 3 hours and driven for less than 1 mile (1.6 km) in that 3 hour period.
Allow the tire to cool before measuring the inflation pressure. Always be sure the tire is cold before inflating to the recommended pressure.
Hyundai Elantra AD (2016-2020) Service Manual: Line Pressure Control Solenoid Valve Description and Operation
Description
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Line pressure control solenoid valve is attached to the valve body.
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This variable force solenoid valve indirectly controls the hydraulic pressure inside the line pressure. ...
Hyundai Elantra AD (2016-2020) Service Manual: General Information
General
1.
This measurements are provided as reference for A/S, so it can not be used as specification.
2.
Basically, all measurements in this manual are taken with a tracking gauge.
3.
When a measuring tape is used, check to be sure there is no elongation, twisting or bending.
4.
...