If you are wondering how to reset tire pressure sensor lights on a Ram, the answer is usually that the truck resets itself. Fill the low tire to the cold pressure on the tire information label, then drive: Ram's owner's manual says the truck may need to be driven for up to 20 minutes above 24 km/h for the system to receive the new pressures, and the warning light then turns off. A light that flashes and then stays on is a different message, and if it will not clear, book a tire pressure sensor check with our service team in Portage la Prairie.
That second case is common in Manitoba every October, when trucks go onto their winter wheels. A winter set without working sensors leaves the system with nothing to read, and the light tells you so every time you drive. Below is how the sensors work, the reset that fixes a low tire, and what to do when the light will not go out. For the cold morning side of the story, see our post on why the tire pressure light comes on in cold weather.
Key Takeaways
- Most of the time there is nothing to press. Ram's owner's manual says that once the system receives the corrected pressures, it updates on its own and the warning light turns off.
- Fill cold, to the label. The manual says to inflate a low tire to the vehicle's recommended cold placard pressure, and that a warm tire may need up to an extra 28 kPa (4 psi) above that figure before the light goes out.
- Then drive. The truck may need up to 20 minutes above 24 km/h for the system to receive the new pressures.
- Flashing is a fault, not a low tire. The manual says the light flashes for 75 seconds and then stays on when the system has a fault, such as a wheel without a sensor, snow or ice around the wheels, or tire chains.
- Winter wheels need sensors too. A winter set without working sensors keeps the fault light on all season.
How Tire Pressure Sensors Work
Each road wheel on a truck with a direct tire pressure monitoring system carries a small sensor, usually built into the valve stem inside the wheel. It reads the pressure in that tire and sends it by radio to the truck, which compares it with where it should be.
When a tire drops low, Ram's owner's manual says the warning light comes on and the instrument cluster shows the affected tire in a different colour with an "Inflate to" message. The figure to fill to is the cold pressure on the tire information label on the driver's door edge or door post; if the message ever shows a different number, go by the label and ask our service team to take a look. When the system itself cannot read a tire, it shows a fault instead, which is why the light can mean two different things.
Two points follow from that:
- The system reads the four road tires. A spare without a sensor is not part of it, and the manual describes a fault warning when a spare without a sensor is put on in place of a road tire.
- It is a warning, not a gauge. It tells you when a tire has dropped. A monthly check with your own gauge tells you before it gets there, and our guide to Ram 1500 tire pressure shows where the right numbers are printed.
How to Reset the Tire Pressure Light After Adding Air
This is the reset for a solid light caused by a low tire, which is the one most drivers see on the first cold morning of the fall.
- Check the tires cold. Take the reading before you drive, with your own gauge, so you know which tire is low and by how much.
- Fill to the label. Ram's owner's manual says to inflate a tire with a low pressure condition to the vehicle's recommended cold placard pressure. The tire information label on the driver's door edge or door post gives that figure, front and rear.
- Allow for warm tires. If you are filling after a drive, the manual says the pressure may need to be up to 28 kPa (4 psi) above the cold placard pressure to turn the warning light off. Set it back to the label the next time the tires are cold.
- Drive. The manual says the vehicle may need to be driven for up to 20 minutes above 24 km/h for the system to receive the new pressures. A run on the highway does it faster than a few blocks in town.
- Watch the light go out. Once the system receives the updated pressures, the manual says the display returns to its normal colour and the warning light turns off.
On a Jeep, Dodge or Chrysler, the owner's manual for your model year describes its own system, so start there before you look for a button or a menu.
Why the Light Will Not Reset
If the light is solid and stays on after a drive, read the tires again with a gauge. A tire that is still under the label, or one with a slow leak that drops between the gas station and home, will keep the light on.
If the light flashes, the message is different. Ram's owner's manual says that when the system has a fault, the warning light flashes on and off for 75 seconds and then stays on solid. The manual lists these causes of a system fault:
- signal interference from electronic devices or facilities sending on the same radio frequencies as the sensors
- aftermarket window tinting with materials that may block radio signals
- snow or ice built up around the wheels or wheel housings
- tire chains
- wheels or tires not equipped with sensors
The manual says the light stops flashing and the display returns to normal once the fault no longer exists. Snow packed into the wheel wells after a drive down a drifted grid road can clear itself as it melts. A wheel without a sensor will not, and neither will a sensor that has stopped working, which is the point at which the truck needs a look.
Winter Wheels and Tire Pressure Sensors in Manitoba
Plenty of Manitoba drivers keep a second set of wheels for their winter tires, which makes the fall swap quicker and spares the bead of the tire. Our post on winter tires on rims or swapped onto your wheels covers that choice.
The catch is the sensors. If the winter wheels were bought without sensors, the system has nothing to read once they go on, and the fault light shows up every time you drive. Before you buy a winter set, or before you put an old set back on, ask our service team whether it has sensors that work with your truck.
Our service department supplies and installs new tires and does seasonal tire changeovers. We are also a participating retailer in the MPI Winter Tire Program. As of October 1, 2026 the program covers tires marketed solely as winter tires; all weather and all season tires no longer qualify, even with the mountain snowflake mark. Manitoba Public Insurance sets who is eligible, and our guide to the MPI Winter Tire Program explains how it works.
What the Usual Fix Involves
If a gauge shows the tires are right and the light still flashes, the fix depends on the cause. A tire with a slow leak gets repaired or replaced. A sensor that has stopped reporting gets replaced and introduced to the truck. A winter wheel without a sensor gets one fitted. Our service department does electrical repair, including sensors, and diagnosis of warning lights; ask our service team which of these your truck needs when you book it in.
FAQs
How do I reset the tire pressure sensor on a Ram?
Usually you do not have to press anything. Fill the low tire to the cold pressure on the tire information label and drive. Ram's owner's manual says the truck may need to be driven for up to 20 minutes above 24 km/h for the system to receive the new pressures, and the warning light then turns off on its own.
How long does it take for the tire pressure light to go off?
Up to 20 minutes of driving above 24 km/h, according to Ram's owner's manual. If you filled the tires warm, the manual says the pressure may need to be up to 28 kPa (4 psi) above the cold placard figure before the light goes out.
Why is my tire pressure light flashing?
A flashing light is a system fault, not a low tire. Ram's owner's manual says the light flashes for 75 seconds and then stays on when the system has a fault, and lists causes that include wheels or tires not equipped with sensors, snow or ice around the wheels, tire chains, and radio interference.
Do winter wheels need tire pressure sensors?
For the warning system to work, yes. Without working sensors in the winter wheels, the system has nothing to read and shows a fault every time you drive. Ask our service team whether your winter set has sensors that work with your truck before the swap.
How do tire pressure sensors work?
A sensor in each road wheel, usually part of the valve stem, reads the pressure in that tire and sends it by radio to the truck. Ram's owner's manual says the truck turns the warning light on and shows the affected tire in the cluster when the pressure is low.
Can I keep driving with the tire pressure light on?
Not for long. Ram's owner's manual says that when the low pressure warning comes on, you should stop as soon as possible and inflate the low tire to the recommended cold placard pressure. If the light is flashing rather than solid, check the pressures with a gauge and book a sensor check.
The Bottom Line
Knowing how to reset tire pressure sensor lights mostly means knowing which light you have. A solid light after a cold night means a low tire: fill it to the label and drive, and the truck resets itself. A light that flashes and then stays on means the system cannot read a sensor, and no amount of air will clear it.
If the light will not clear, or your winter wheels need sensors, book a visit with our service team. And if you are shopping for a heavy duty truck, you can browse our new Ram 2500 inventory from anywhere in Manitoba.
Tyler Dunn, Dunn Ram Trucks, Portage la Prairie
