Tire pressure light on solid: one or more tires is low

Both manuals say the TPMS illuminates a low tire pressure telltale when one or more tires is significantly underinflated, and that when it comes on, you should stop and check your tires as soon as possible and inflate them to the proper pressure.

Driving on a significantly underinflated tire causes the tire to overheat and can lead to tire failure. Underinflation also reduces fuel efficiency (the Ram manual says vehicle range) and tire tread life, and may affect the vehicle's handling and stopping ability.

Do not continue driving with one or more flat tires, both manuals add, as handling may be compromised; stop the vehicle, avoiding sharp braking and steering.

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (Tire Pressure Monitoring System (TPMS) Warning Light), read October 27, 2026.

Tire pressure light flashing: the system has a fault

The TPMS malfunction indicator shares the low tire pressure telltale. When the system detects a malfunction, the telltale flashes for approximately one minute and then stays on. In the detailed TPMS sections of both manuals, the light flashes on and off for 75 seconds, then stays on solid, a chime sounds, and the cluster shows a "SERVICE TPM SYSTEM" message, then dashes (--) in place of the pressure for the sensor that is not being received. The sequence repeats each time the vehicle is started while the fault exists.

While the malfunction indicator is on, the system may not be able to detect or signal low tire pressure as intended. A system fault can be caused by:

• Signal interference from electronic devices, or driving next to facilities that emit the same radio frequencies as the TPMS sensors.
• Lots of snow or ice around the wheels or wheel housings.
• Using tire chains on the vehicle.
• Using wheels or tires that are not equipped with TPMS sensors.
• Aftermarket window tinting that contains materials that may block radio wave signals (Ram manual).

Replacement or alternate tires or wheels can also keep the TPMS from working properly, so the manuals say to check the TPMS malfunction telltale after replacing one or more tires or wheels.

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (TPMS Warning Light; Service TPMS Warning), read October 27, 2026.

Why the tire pressure light comes on when it gets cold

The Ram manual says tire pressure changes by about 1 psi (7 kPa) for every 12°F (6.5°C). When the outside temperature drops, tire pressure drops with it, and the TPMS warns of low pressure for any reason, including low temperature and natural pressure loss through the tire.

The Ram manual gives an example: with a recommended cold placard pressure of 30 psi and a measured 27 psi at 68°F, a drop to 20°F lowers the pressure to about 23 psi, low enough to turn the light on. Driving may warm the tires back up to about 27 psi, but the light stays on until the tires are inflated to the recommended cold placard pressure.

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (Tire Pressure Monitoring System (TPMS)), read October 27, 2026.

How to turn the tire pressure light off

The light turns off only after the low tires are inflated to the recommended cold placard pressure. To clear it:

1. Find the recommended cold tire pressure on the tire placard. In the Ram manual it is on the driver's side B-pillar or the rear edge of the driver's side door.
2. Inflate the low tire or tires to that pressure. When filling warm tires, you may need to add up to 4 psi (28 kPa) more than the cold placard pressure to turn the light off.
3. Never exceed the maximum inflation pressure molded into the tire sidewall (Ram manual).
4. Drive. The system updates on its own once it receives the new pressures, which can take up to 20 minutes of driving above 15 mph (24 km/h).
5. Reinstall each valve stem cap, which keeps moisture and dirt out of the valve stem and away from the TPMS sensor.

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (Tire Pressure Monitoring System (TPMS); Tire Loading And Tire Pressure), read October 27, 2026.

Spare tires, sealants and aftermarket wheels

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (TPMS cautions and notes; Vehicles With Non-Matching Full Size Spare Or Compact Spare), read October 27, 2026.

How to check tire pressure the right way

Check each tire, including the spare if your vehicle has one, monthly and when cold, with an accurate tire pressure gauge, and inflate to the pressure on the vehicle placard or tire inflation pressure label. In the Ram manual, cold means the vehicle has not been driven for at least three hours, or has been driven less than 1 mile (1.6 km) after a three-hour stop. Pressure rises as you drive; that is normal, and you should not let air out to adjust for it.

The manuals also say the driver is responsible for keeping the correct tire pressure even if underinflation has not yet reached the level that turns on the light.

From the 2026 Ram 1500 Owner's Manual and the 2026 Jeep Grand Cherokee Owner's Manual (TPMS; Tire Pressure Monitoring System (TPMS) notes), read October 27, 2026.

Tire service at Elgin Auto Sales & Service Center

We service all makes and models. If your tire pressure light keeps coming back, or it is flashing, schedule service online and choose tire rotation, tire balancing or a front-end alignment, or add a note about the light so your technician can look at the tires and the system.

Our service department is open Monday to Friday 8 a.m. to 5 p.m. and Saturday 8 a.m. to 4 p.m., closed Sunday. Elgin Auto Sales & Service Center is at 1200 E. Chicago St. in Elgin. Get directions.

Schedule service online, or see our service specials.