DIY Lincoln MKX Tire Pressure Sensor Fault Repair

When the TPMS warning light flashes in your Lincoln MKX, it’s important to heed the warning. Under-inflated tires decrease fuel efficiency, wear out more quickly and may cause handling issues.

Make sure to check the tire pressure on each of your wheels when the weather is warmer. It’s also best to set your tire pressure to the recommended psi at room temperature when you do this.

1. Check the Battery

The tire pressure sensors in your Lincoln MKX are powered by built-in lithium batteries. These batteries tend to deplete over time due to constant exposure to the elements. When the batteries run low the sensor will stop transmitting air pressure information to the receiver module, which triggers the TPMS warning light to illuminate.

The battery in your car can last up to 5 years, depending on the weather conditions and driving habits. To increase the life of your battery, make sure to keep the terminals clean and avoid leaving the vehicle parked for long periods of time. The battery will also be susceptible to corrosion over time, but you can easily protect your vehicle’s battery by using a specialized cleaning solution and wire brush.

Checking the air pressure in your tires is relatively easy and should be done on a regular basis. Underinflated tires can affect your gas mileage and cause unsafe handling dynamics, while overinflated tires waste fuel and wear out more quickly. Ideally, you should inflate your tires to the factory recommended air pressure indicated on the vehicle placard or tire inflation pressure label, which is usually located on the B-pillar or edge of the driver door.

Once you’ve inflated the tires to their proper air pressure, the TPMS light should turn off automatically. However, if the indicator light continues to flash, then it could be a sign of a faulty sensor or sensor battery.

2. Remove the Sensor

Each sensor transmits a radio frequency signal to the SJB (or BCM in later models) every 60 seconds when the vehicle is moving at 20 mph or higher. The transmission is compared against a low-pressure limit (the pressure listed on the tire certification label minus 25%, which will be about 6 to 9 psi). If the SJB detects that the sensor’s pressure has fallen below this level, it will illuminate the TPMS warning light and display the appropriate message(s) in the message center (if equipped).

If the amber colored TPMS warning light in your Lincoln MKX stays on even after you reinflated all of the tires to their proper air pressure as specified on the vehicle’s tire pressure certification label, it may mean that one or more of the sensors have failed. It could also mean that the TPMS receiver module has malfunctioned or that the battery in the sensor is dead.

The best way to diagnose and fix a bad tire pressure sensor is to use an advanced diagnostic scanner like MaxiTPMS TS408, which will scan the individual sensor for fault codes. If the scanner indicates that the sensor is faulty or that the sensor’s battery is dead, then you will need to replace the sensor.

If the TPMS warning light still remains on after you have fully reinflated all of the tires to their appropriate pressure as specified on the tire certification label, follow these steps to reset the system:

3. Disconnect the Wires

Unlike vehicles with indirect TPMS systems, Lincoln MKX has a direct tire pressure sensor that actively records the internal air pressure on each wheel. As a result, there is no reset button to push when the tire pressure light illuminates. In order to reset the MKX tire pressure warning light, you must increase the air pressure in each tire by 5 psi over the manufacturer’s recommended value and drive the vehicle for at least two minutes at 20 mph (32 km/h).

One of the most common causes of the TPMS low air pressure warning light is cold weather. This is because the air expands when heated and contracts when cooled. This changes the air pressure inside each tire, which triggers the sensor to alert the driver.

To test the tire pressure sensor battery, first disconnect the wires from the sensor. Then, use a multimeter to measure the resistance of the circuit wiring. Connect the red probe to the + wire going to the sensor and the black probe to the ground wire connected to the sensor. Set the multimeter to read Ohms and choose the ohm value that is closest to, but higher than 200O. This will help to identify the wiring issue and determine if the battery is bad or if the ohm readings indicate a shorted circuit.

4. Replace the Sensor

It is possible that the sensor itself is faulty and needs to be replaced. In this case, you will need to jack up the car and locate the sensor which will look like a spark plug with black wires coming out of it. It is probably a good idea to have some help lifting the vehicle as working under it can be dangerous. After finding the sensor, remove the wiring from it. It is a good idea to spray some penetrating oil around the sensor socket, or even soak it in it to make it easier to remove. You may need to heat it up with a torch to loosen the sensor bung as it can be tight. Once the sensor is removed, replace it with a new one and plug the wiring back in.

Once you have the replacement sensor, you can reinflate your tires to the recommended pressure listed on the tire certification label (found in the driver’s door or door pillar). Then activate the new sensor by driving at 20 mph for at least two minutes using the Lincoln TPMS Sensor Activation Tool.

It is important to know that the TPMS warning light will be on while the tire pressure sensors are being activated. This is because the air in the tires expands when it is heated and contracts when cooled. This can cause the sensor to drop in internal pressure and trigger a low tire pressure warning light. If you are unable to reset the light, you should visit Auffenberg Dealer Group so that our technicians can isolate the problem and repair it.

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