Lincoln MKX low tire pressure warning light causes, how to reset

Lincoln MKX is equipped with Tire Pressure Monitoring System (TPMS) for the purpose of warning the driver when one or more of the tires are significantly under-inflated, creating a potentially unsafe driving condition. In this article we discuss the reasons for the amber colored TPMS warning light in MKX, and how you can reset it.

Lincoln MKX
Lincoln MKX – (Art Konovalov / Shutterstock)

The TPMS warning light illuminates in Lincoln MKX when air pressure is low in one or more of the tires, battery has depleted in a pressure sensor, TPMS receiver module has malfunctioned, or a pressure sensor has been damaged.


Low tire pressure

When the amber colored TPMS warning light turns on in your MKX, stop your vehicle when it is safe to do so and check tire pressure on all the wheels, including the spare wheel (if your vehicle has one). Driving on a significantly under-inflated tire causes the tire to overheat and can lead to tire failure.

Reinflate the tires

Reinflate all the tires of your MKX to the manufacturer specified air pressure, which is mentioned on the vehicle placard or tire inflation pressure label usually located on the B-pillar or the edge of the driver door. If you can’t find the label, check the size of your tire which is mentioned on the sidewall of the tire, and match it to the tire pressure information shown below.

  • 245/60R18: 33 psi
  • 245/50R20: 33 psi
  • 265/40R21/XL: 35 psi
See the sidewall of any tire on your MKX to find the tire size information.

Resetting the TPMS warning light

After you have inflated all the tires to the correct air pressure, the TPMS warning light will turn off automatically. The vehicle must be driven for at least two minutes over 20 mph (32 km/h) before the light turns off. Lincoln MKX uses the direct method for monitoring tire pressure, which means a pressure sensor actively records the internal pressure and air temperature of the tire on each wheel. There is no need to reinitialize the TPMS system in order to reset the warning light. There is no reset button like the one you see in vehicles with indirect TPMS system which uses ABS sensors to detect low tire pressure.

If the low tire pressure light does not turn off automatically after reinflating the tires in your MKX, increase the tire pressure by 5 psi on top of the factory recommended value, and drive your vehicle for at least 10 miles (16 km). After the TPMS warning light turns off, and the vehicle has been parked for a few hours, reduce the tire pressure to the factory recommended value.

Chilly weather can turn on low tire pressure light in MKX

Cold weather is one of the most common cause for low tire pressure warning light in Lincoln MKX. When analyzing WheelsJoint’s statistical data, it has been observed that there is sharp rise in the number of searches for TPMS warning light causes at the start of every winter season, about three times higher as compared to mid summer season.

The air, like most other substances, expands when heated and contracts when cooled. So when the weather gets colder, the tire pressure decreases, which could trigger TPMS warning light in MKX. The tire pressure will vary with temperature by about 1 psi (7 kPa) for every 12°F (6.5°C).

Tire pressure vs temperature: This chart shows how tire pressure of 35 psi at temperature of 35°C (95°F) decreases by roughly 1.6 psi with every 10°C (18°F) drop in temperature.

Inflate tires when cold

Tire pressure in MKX should always be set based on cold inflation tire pressure. This is defined as the tire pressure after the vehicle has not been driven for at least three hours, or driven less than 1 mile (1.6 km) after a three-hour period.


Do not adjust tire pressure when hot

The tires on your MKX can get around 50 degrees hotter than the outside temperature when you’re driving, which increases the tire pressure by about 4 psi – this is normal and there should be no adjustment for this increased pressure.

Does altitude affect tire pressure?

Yes, altitude can change tire pressure values, but it is negligible and not a cause for concern. If you drive your MKX from sea level to Mount Evans Scenic Byway in Colorado which is the highest paved road in North America at the altitude of 14,130 feet (4,307 m), the tire pressure should theoretically increase by approximately 6 psi. But, the decrease in ambient temperature at higher elevation contracts the air in tires and compensates for any altitude pressure changes.

Is it safe to drive MKX with low tire pressure?

The driving characteristics of MKX change even if the air pressure is 5 psi less than manufacturer’s recommended value: the braking distance can be longer, cornering worse, and at particularly high speeds there is even a risk that the tire will burst. Low tire pressure also increases tire wear, and the higher rolling resistance of the tire means higher fuel consumption. So it is recommended to reinflate the tires to the correct pressure as soon as possible.

Dead battery in a tire pressure sensor

Each tire pressure sensor in MKX is powered by a built-in lithium-ion battery. When the battery is depleted, the sensor stops transmitting tire pressure information to the receiver module. When this happens, the TPMS warning light will flash every time the engine is started, and will remain illuminated until you turn off the vehicle.

How long do the pressure sensor batteries last?

The tire pressure sensor batteries usually last anywhere from 5 to 10 years in MKX. When the battery is depleted, you must replace the sensor itself, as the battery is sealed into the sensor unit and is non-replaceable.

Identifying a faulty pressure sensor

The most reliable method for detecting a faulty tire pressure sensor or a sensor with dead battery is by testing each sensor with a scan tool. For example, MaxiTPMS TS408 is commonly used for diagnosing and programming tire pressure sensors. A sensor that is not detectable by the scanner is most likely defective and should be replaced with a new one.

Scan each wheel with a scan tool like MaxiTPMS TS408 and see which one does not respond.

If you don’t want to spend over a hundred bucks on a scanner, then head over to any reputable tire shop and perform a TPMS diagnostic scan of your MKX. Some shops like Discount Tire and Pep Boys offer free of charge TPMS diagnostic services.

Installed new tires?

If a pressure sensor stopped responding after you installed new tires on your MKX, it is possible the sensor got damaged during tire installation. These sensors are quite sensitive, and can be easily damaged if utmost care is not taken while changing tires.


Lincoln MKX TPMS warning light meaning

The main function of the tire pressure monitoring system is to warn you when your tires need air. It can also warn you in the event the system is no longer capable of functioning as intended. See the following chart for information concerning your tire pressure monitoring system:

Solid warning light

Tire(s) under-inflated: Make sure tires are at the proper pressure. See Inflating your tires in this chapter. After inflating your tires to the manufacturer’s recommended pressure as shown on the Tire Label (located on the edge of driver’s door or the B-Pillar), the vehicle must be driven for at least two minutes over 20 mph (32 km/h) before the light turns off.

Spare tire in use: Repair the damaged road wheel and tire assembly and reinstall it on the vehicle to restore system function.

TPMS malfunction: If the tires are properly inflated and the spare tire is not in use but the light remains on, contact your authorized dealer as soon as possible.

Flashing warning light

Spare tire in use: Repair the damaged road wheel and tire assembly and reinstall it on the vehicle to restore system function.

TPMS malfunction: If the tires are properly inflated and the spare tire is not in use but the light remains on, contact your authorized dealer as soon as possible.

Reset the entire system

If the low tire pressure warning light won’t turn off due to a glitch in the tire pressure monitoring system, it may be possible to reset the TPMS system by resetting all on-board computers in your MKX. This method should only be considered as a last resort, when all else fails.

Disconnect both negative and positive terminals of the battery.

You can reboot all the on-board computers by disconnecting the main 12 volt battery for a few minutes. Remove the cable from the negative terminal of the battery first, then from the positive terminal. With the battery disconnected, press the horn button a few times and turn on the headlights to drain out all the residual electricity from the system. After about 15 minutes, reconnect the battery in reverse order: positive cable first, then negative cable.

Tire pressure keeps getting low

If the TPMS warning light turns on frequently in your MKX, and the tire pressure is also decreasing after you have reinflated the tires, there may be an air leak. One or more of the tires may have been punctured by an external object, or the air may be leaking from a defective value stem.

A punctured tire can be plugged with a tire repair kit if the puncture is not near the sidewall.

Can I disable the TPMS system in MKX?

No, the TPMS system is federally mandated, and cannot be disabled in Lincoln MKX. All vehicles must have a working tire pressure monitoring system to be legally compliant.

Use OBD2 scanner for diagnosis

Since Lincoln MKX is equipped with on-board diagnostics (OBD), a fault diagnosis can provide initial indications of where the malfunction is located. But when it comes to TPMS, a basic code reader will not suffice. You will need an advanced scanner to monitor TPMS data or read TPMS codes.

BlueDriver is a Bluetooth based diagnostic device which you can connect to the OBDII port in your vehicle and use your mobile phone for diagnosis. You will need to download the “BlueDriver OBD2 Scan Tool” app from the App Store on your iPhone, or from Google Play Store if you have an Android phone.

BlueDriver is a commonly used scanner by DIYers that can read TPMS codes for most vehicles and isn’t too expensive – costs about a hundred bucks. You can also clear the TPMS fault codes with this device which will turn off the warning light, but the light may come back on if the on-board diagnostic system detects a fault again.

Author: Nabeel K
Email: nabeel@wheelsjoint.com



Subscribe
Notify of
guest

0 Comments
Inline Feedbacks
View all comments