The tire pressure warning light warns you that the tire pressure is too low. It looks like a cutaway tire with an exclamation point. Almost half of the people don’t seem to know what this warning light means when it comes to the dashboard of their car.
Table of contents
- TPMS light vs tire pressure light
- Main causes to come on
- Importance of the correct tire pressure
- How to check tire pressure
- How to reset the tire pressure light
- Fix low tire pressure light
- Normal PSI (Pounds per Square Inch)
- TPMS sensor
TPMS light vs tire pressure light
To begin with, you need to know the difference between the TPMS light indicator and the tire pressure light.
The tire pressure light comes on when the tire pressure is between 18 and 25 percent below its recommended value listed on the driver’s door sticker. This may vary from car to car. Often, there are tire pressure differences between the front and rear wheels of the vehicle.
The TPMS sensor comes on and stays on when there is a serious problem with the TPMS, also known as the Tire Pressure Monitoring System. The TPMS is an electronic system inside your tire that monitors the air pressure in your tires.
Main causes to come on
There are several reasons why the tire pressure light is blinking on the dashboard of your vehicle. Here’s an overview:
- Slow leaking punctures in the tread (nail in the tire)
- A damaged rim (scratches, cracks, rust,…)
- An incorrectly placed valve or missing valve caps
- Tightening the TPMS sensor too hard
- Micro-cracks in the inner layer that protects the tire
- Temperature drop in the winter
- Small breaks or cuts on the tire
- Damage to the tire during disassembly of the tire on the rim
- The spare tire doesn’t have a TPMS sensor
Importance of the correct tire pressure
Correct tire pressure is very important and crucial to prevent accidents. Low tire pressure is more dangerous compared to high tire pressure. As you can see in the image below, when tires are deflated, more rubber touches the ground. This causes the tires to head up and you are in danger of a blowout.
Higher pressure generally is not dangerous, as long as you stay well below the “maximum inflation pressure.”
Tires will naturally lose 1 to 1.5 pounds of pressure each month. If it has been 6 months since you last checked your tires, you could be running 8-9 psi below normal.
How to check tire pressure
As we mentioned before: the correct tire pressure is very important for the safety of your vehicle. It is very easy to check the tire pressure yourself. All you need is a tire pressure gauge, an air compressor, pen, and paper. Follow these steps to check the tire pressure of your vehicle.
#1 Start with cold tires
To check the pressure, it is important that your tires are cold. Tires are considered cold when the car has been parked for four hours or more.
#2 Find the correct PSI for your vehicle
You can find the correct PSI for your vehicle on the driver’s side door jamb or on the owner’s manual.
#3 Write down the correct PSI for each tire
Be very attentive during this step. Often, there are tire pressure differences between the front and rear wheels of the vehicle.
#4 Check the pressure with the gauge
Use the tire pressure gauge to check the current tire pressure.
#5 Fill to the recommended PSI
Fill the tires with low pressure. You can use an air compressor to do this. After this is done, check the tire pressure again, as we showed in step 4.
How to reset the tire pressure light
There are a few things you could do to reset the tire pressure light (or TPMS). Here is an overview.
Most cars (certainly the newer ones) have a TPMS reset button under the steering wheel (see Honda example below). You can push this button to reset the TPMS. Put the car key in the ignition and turn on the battery but don’t start the vehicle. Push the TPMS reset button for about 3 seconds or until the system’s warning light starts blinking. Start the vehicle and drive for 20 to 25 minutes, then turn off the ignition.
#2 Deflate and reinflate the tires
Another thing you could try is deflating and reinflating the tires until they have the correct pressure. You can use a tire pressure gauge to check the tire pressure.
Inflate each tire to its ideal PSI then deflate the tires to zero. Then inflate again and drive for a couple of minutes to manually calibrate the TPMS sensors.
#3 Disconnect and reconnect the car’s battery
The onboard computer from your vehicle may face a glitch from time to time. The best way to fix these glitches is to reset the computer. You can do this by disconnecting and reconnecting the battery. Make sure you reconnect properly otherwise your battery light might come on.
#4 Drive 10 miles at 50mph at a constant speed
This might be the easiest method as it requires you to just drive your car at 50 mph for about 10 miles and the TPMS sensors will automatically calibrate themselves. Some vehicles require higher speed and you can also use the cruise control to keep the speed constant.
#5 Use an OBD2 scanner
An OBD2 scanner is a very powerful device. It is the easiest and fastest way to find the problem when your tire pressure warning light appears on your dashboard. The device reads the trouble codes from your vehicle. These codes are stored in one of your control units.
Always make sure the tools are compatible with your vehicle before you are making any purchase.
An OBD2 scanner is also used to detect problems with the EPC light.
Fix low tire pressure light
Follow these 5 steps to fix a low tire pressure issue.
#1 Find the correct PSI or tire pressure
Find the correct tire pressure or PSI for your tires. Often, you will find this online if you search for the model of your car. If you don’t find your car type, take a look at your wheels. Normally, they will have the maximum PSI for each tire written on the side.
#2 Find yourself an air pump
Find yourself an air pump. These are usually located at most garages (service center) or gas stations for free or for a small charge. You can also buy them yourself, for example on Amazon.
#3 Remove the valve stem
Now, remove the valve stem for each tire. Make sure to put them somewhere safe because they get lost easily.
#4 Inflate the tires
Pop the air hose over the stem and push the hose into the vale. Inflate the tires with the air pump. Make sure that you don’t over-inflate. Keep an eye on the screen of the pump.
#5 Remove the air pump and pop the valve stem back
Remove the air pump and pop the valve stem back. Repeat this process for all other tires with low tire pressure. After you did this, the tire pressure light should go out.
Normal PSI (Pounds per Square Inch)
What PSI should your car tires be? Well, normal tire pressure is usually about 32 PSI (when properly inflated). The tire pressure is often listed on the driver’s door sticker and in the owner’s manual.
PSI is a unit of pressure expressed in pounds of force per square inch of area. It stands for Pounds per Square Inch.
1 PSI = 6894 Pascals = 0.070 atmospheres = 51.715 torr
The TPMS sensors are located in the tire pressure valve or are wrapped around the rim of the wheel with a band clamp.
In Europe, most TPMS sensors are located within the ABS braking system and the speed sensors for each wheel.