A tire monitor fault warning means your vehicle's tire pressure monitoring system (TPMS) has detected a problem — either low pressure in one or more tires, a sensor malfunction, or a dead sensor battery
The warning light on your dashboard (usually a tire with an exclamation mark) tells you the TPMS cannot reliably report tire pressure. This is not the same as a straightforward low-tire warning. A fault means the system itself is broken or one of its sensors has stopped working, so you cannot trust the pressure readings it would normally give you.
Your first step is to check all four tire pressures manually with a gauge. If all tires are at the correct pressure for your vehicle (found on a sticker inside the driver's door or in your owner's manual), the problem is a faulty sensor or wiring issue. If one or more tires are low, inflate them to the correct pressure and see whether the warning clears after driving for a few minutes. If the warning stays on after you have corrected the pressure, you have a sensor problem.
Key Takeaways
- A tire monitor fault warning means your TPMS sensors or wiring have a problem, not necessarily that your tires are low on pressure.
- Check all four tire pressures manually with a gauge to rule out straightforward underinflation before assuming a sensor has failed.
- TPMS sensors use coin-cell batteries that typically last five to seven years and will trigger a fault warning when they die.
- A single faulty sensor usually costs $50 to $150 to replace, depending on whether you use OEM or aftermarket parts and whether you install it yourself.
- Driving with a TPMS fault is legal but risky because you lose real-time pressure monitoring, which can mask a slow leak or blowout risk.
Why TPMS sensors fail and what causes a fault warning
TPMS sensors are small wireless transmitters mounted inside each wheel. They measure tire pressure and send that data to a receiver in your vehicle. Each sensor contains a battery that powers the transmitter. When the battery dies — typically after five to seven years — the sensor stops sending signals, and your vehicle displays a fault warning.
Sensors can also fail if the battery corrodes, the transmitter circuit breaks, or the antenna inside the sensor is damaged. Corrosion happens most often in humid climates or after the vehicle has been parked for a long time. Physical damage occurs when a tire shop dismounts a tire carelessly or when road debris strikes the wheel.
Wiring problems between the sensors and the receiver are less common but possible. A corroded connector, a pinched wire, or a failed receiver module can prevent the vehicle from receiving sensor signals even if the sensors themselves are working.
How to tell whether the problem is low pressure or a faulty sensor
Start by checking tire pressure in all four tires using a manual pressure gauge. You can buy a basic gauge for $5 to $15 at any auto parts store, or use the air pump at a gas station (most have a built-in gauge). Write down the pressure in each tire and compare it to the correct pressure listed on the door jamb sticker or in your owner's manual.
If all four tires are at or near the correct pressure, the fault is a sensor or wiring problem. If one or more tires are low, inflate them to the correct pressure and drive the vehicle for five to ten minutes. The warning should clear once the system detects that pressure is normal. If the warning stays on after you have corrected the pressure, that tire's sensor is faulty.
Pay attention to which tire the warning is associated with, if your vehicle's display shows that information. Some vehicles display a specific tire location (front left, rear right, and so on); others show only that a fault exists. If your vehicle shows the location, that tells you which sensor to replace first.
Replacing a faulty TPMS sensor
Replacing a sensor requires removing the tire from the wheel, unbolting the old sensor from the valve stem, and installing a new one. This is a job most tire shops handle routinely. The cost depends on whether you use an original equipment manufacturer (OEM) sensor or an aftermarket replacement, and whether you do the work yourself or pay a shop.
OEM sensors typically cost $40 to $100 each, while aftermarket sensors run $20 to $60. Labor at a tire shop usually adds $15 to $50 per sensor. If you are comfortable working on your vehicle, you can buy a sensor and install it yourself using basic hand tools, which saves the labor cost. Some aftermarket sensors are designed to be easier to install than others, so read reviews before buying.
After you install a new sensor, you may need to have the vehicle's TPMS receiver reprogrammed to recognize it. Some vehicles do this automatically after you drive for a few minutes; others require a technician to use a TPMS programming tool. Your vehicle's manual or the sensor packaging will tell you whether reprogramming is needed. Many tire shops include this service in their sensor replacement price.
When to replace all four sensors at once versus one at a time
If only one sensor is faulty, you can replace just that one. However, if your vehicle is older than seven years and has the original sensors, all four batteries are likely near the end of their life. Replacing them all at once costs more upfront but saves you from having another sensor fail a few months later.
Some shops offer a discount if you replace all four sensors together. Ask about this when you call for a quote. If you are replacing tires anyway, it is often a good time to replace aging sensors, since the tires are already off the wheels.
If your vehicle is newer and only one sensor has failed, replacing just that one is reasonable. Keep track of when you replace it so you know when the other three are likely to fail.
Is it safe to drive with a TPMS fault warning?
Driving with a TPMS fault is legal in all U.S. states, but it is not safe in the long term. The TPMS exists to alert you to pressure loss that could cause a blowout or poor handling. Without a working system, you lose that early warning. A slow leak in a tire might go unnoticed until the tire is dangerously low.
You can drive to a tire shop or repair facility to have the sensor replaced without risk, as long as you drive at normal highway speeds and do not take the vehicle on a long trip. Check your tire pressures manually every week or two until the sensor is fixed. If you notice any tire is significantly lower than the others, have it inspected for a leak before driving further.
Do not ignore a TPMS fault for months. Sensor batteries are inexpensive to replace, and the cost of a new sensor is far less than the cost of a blowout or accident caused by undetected pressure loss.
Aftermarket sensors versus OEM sensors
OEM sensors are made by the vehicle manufacturer or a supplier contracted by the manufacturer. They are may provide to work with your specific vehicle and usually come with a warranty. Aftermarket sensors are made by third-party companies and are often cheaper, but quality varies widely.
Some aftermarket sensors are programmable, meaning you can set them to match your vehicle's tire pressure specifications before installation. Others are pre-programmed for a specific vehicle model. Read the product description carefully to make sure the sensor is compatible with your vehicle.
For most vehicles, a quality aftermarket sensor works just as well as an OEM sensor and costs significantly less. However, if your vehicle is high-end or has a complex TPMS setup, an OEM sensor may be worth the extra cost for peace of mind.
Frequently Asked Questions
Can I ignore a tire monitor fault warning and just check my tires manually?
You can drive safely for a short time if you check tire pressure manually every week, but ignoring the fault long-term is risky. The TPMS is designed to catch pressure loss you might miss, especially in one tire. Replacing a faulty sensor costs $50 to $150 and takes an hour or two — it is worth doing rather than risking a blowout.
Does a tire monitor fault mean I have a flat tire?
Not necessarily. A fault warning means the TPMS cannot report pressure, not that a tire is flat. Check all four tires with a gauge. If they are all at normal pressure, the sensor itself is faulty. If one is low, inflate it and see if the warning clears.
How long can I drive with a faulty TPMS sensor?
You can drive indefinitely as long as you check tire pressure manually every one to two weeks and watch for signs of a leak. However, you lose the automatic early warning the system provides. Replace the sensor within a few weeks to restore full monitoring.
Will the tire monitor fault warning go away on its own?
No. A fault warning means a sensor battery is dead or the sensor is broken. The warning will not clear until you replace the faulty sensor or repair the wiring. Driving will not fix it.
Can I replace a TPMS sensor myself, or do I need a shop?
You can replace a sensor yourself if you have basic hand tools and are comfortable removing a tire. The hardest part is usually unbolting the old sensor from the valve stem. Some vehicles require reprogramming after installation, which may need a shop tool, but many newer vehicles reprogram automatically.