Infiniti QX50 low tire pressure warning light causes, how to reset

Infiniti QX50 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 QX50, and how you can reset it.

Infiniti QX50
Infiniti QX50 – (Teddy Leung / Shutterstock)

The TPMS warning light illuminates in Infiniti QX50 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 QX50, 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 QX50 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. These are official cold tire pressure values for QX50 from Infiniti.

  • P235/ 55RF19: 33 psi
  • P255/ 45RF20: 33 psi
See the sidewall of any tire on your QX50 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. Infiniti QX50 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 QX50, 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 QX50

Cold weather is one of the most common cause for low tire pressure warning light in Infiniti QX50. 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 QX50. 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 QX50 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 QX50 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 QX50 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 QX50 with low tire pressure?

The driving characteristics of QX50 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 QX50 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 QX50. 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 QX50. 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 QX50, 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.


Infiniti QX50 TPMS user guide

TPMS with Tire Inflation Indicator

When adding air to an under-inflated tire, the TPMS with Tire Inflation Indicator provides visual and audible signals outside the vehicle to help you inflate the tires to the recommended COLD tire pressure.

Vehicle set-up:

  1. Park the vehicle in a safe and level place.
  2. Apply the parking brake and press the park button to engage the P (Park) position.
  3. Place the ignition switch in the ON position. Do not start the engine.

Operation:

  1. Add air to the tire.
  2. After a few seconds, the hazard indicators will start flashing.
  3. When the designated pressure is reached, the horn beeps once and the hazard indicators stop flashing.
  4. Perform the above steps for each tire.

If the tire is over-inflated more than approximately 4 psi (30 kPa), the horn beeps and the hazard indicators flash three times. To correct the pressure, push the core of the valve stem on the tire briefly to release pressure. When the pressure reaches the designated pressure, the horn beeps once.

If the hazard indicator does not flash within approximately 15 seconds after starting to inflate the tire, it indicates that the TPMS with Tire Inflation Indicator is not operating.

The TPMS will not activate the TPMS with Tire Inflation Indicator under the following conditions:

  • If there is interference from an external device or transmitter.
  • The air pressure from the inflation device is not sufficient to inflate the tire.
  • There is a malfunction in the TPMS.
  • There is a malfunction in the horn or hazard indicators.
  • The identification code of the tire pressure sensor is not registered to the system.
  • The battery of the tire pressure sensor is low.

If the TPMS with Tire Inflation Indicator does not operate due to TPMS interference, move the vehicle about 1 m (3 ft) backward or forward and try again.

If the TPMS with Tire Inflation Indicator is not working, use a tire pressure gauge.

Using spare tire

When using a wheel without the TPMS such as the spare tire, when a spare tire is mounted or a wheel is replaced, tire pressure will not be indicated, the TPMS will not function and the low tire pressure warning light will flash for approximately 1 minute. The light will remain on after 1 minute. Have your tires replaced and/or TPMS system reset as soon as possible. It is recommended that you visit an INFINITI retailer for this service.

Replacing tires with those not originally specified by INFINITI could affect the proper operation of the TPMS.

Warning: Do not inject any tire liquid or aerosol tire sealant into the tires, as this may cause a malfunction of the tire pressure sensors.

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 QX50. 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 QX50, 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 QX50?

No, the TPMS system is federally mandated, and cannot be disabled in Infiniti QX50. All vehicles must have a working tire pressure monitoring system to be legally compliant.

Use OBD2 scanner for diagnosis

Since Infiniti QX50 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