Why The Tire Pressure Warning System Light In Your Toyota RAV4 Is On and How To Make It Go Out

Tire pressure monitoring systems are mandated by federal law in America. This is not a feature that Toyota installs as an option. For more than a decade, Toyota has been installing systems and they have been driving owners crazy. While they certainly do help let you know if a tire is deflated, in many cases, tire pressure systems are an annoyance.

Here are the reasons that your Toyota RAV4 has a “Tire Pressure Warning System” alert. We will refer to it as TPWS from here forward, which is what Toyota calls it. Before we begin, if your TPWS system warning light is on, immediately check your tire pressure. Some Toyota RAV4 crossovers can display the pressure in the information display. If yours does not, simply use a tire pressure gauge to check the pressures. The correct setpoints are listed on the driver’s door of your vehicle. Do not drive with the TPWS light on without verifying that the tires have proper air pressure.

If you find that the pressure inside all four tires is lower than the setpoint, top them off to the correct pressure. The TPWS light should go out shortly after you set the pressures to the proper psi. If one tire is lower than the rest by more than 30%, have a tire technician investigate.

RAV4 Tire Pressure Warning - Temperatures Have Dropped
If it is fall or early winter and your Toyota RAV4's TPWS warning light is illuminated, the reason is most likely due to the temperature difference between when the pressure was previously set and the current temperatures. Pressures drop with temperature. You need to reset the tire pressures in early winter and early summer. The air didn’t leak out. It simply became lower in pressure as the temperatures dropped. This happens to all tires, in all vehicles, regardless of the gas inside of them. Here's how that works.

RAV4 Tire Pressure Warning - You Have A Flat Or More Than One Flat
The reason you have a tire pressure monitoring system in your Toyota RAV4 is to detect a flat tire. Or multiple flat tires. If you are driving and the light comes on, this is the likely cause for it. Pull to a safe area as quickly as you safely can and investigate. A visual inspection is not enough. Use your tire gauge or the RAV4’s in-dash display to check the pressure in all four tires. If you have a flat, refer to the owner’s manual (see below) on what to do.

RAV4 Tire Pressure Warning - Failure of the TPWS System
Our initial reaction when we get a warning light is to hope it is wrong! They sometimes are. The TPWS system in your RAV4 may have a problem, but it is unlikely. Yes, every person whoever has a problem with the tire pressure system in any car quickly goes to every online forum to report it (angrily). However, the Toyota RAV4 is not a vehicle that struggles with the TPWS system more so than others.

If you have verified the pressure in your tires is correct using a tire gauge and the TPWS system is displaying a warning, ask a mechanic for help with the problem. You don’t have to go to a dealer, but if the RAV4 is under the initial new vehicle warranty that would certainly make sense.

Like any system in your car, age and damage can cause a problem with the TPWS system. Individual sensors can be replaced, but the system will need to be re-initialized. We suggest that this job is best done by a mechanic or tire professional who understands the system and can handle the work.

RAV4 Tire Pressure Warning - Tire Sealants
Tire sealants in a can like Fix-A -Flat, or Slime may cause your TPWS sensor to malfunction. This does not mean that the sensor is destroyed. Here is what Fix-A-Flat says about TPMS systems and its product: “No. Fix-a-Flat is tire sensor safe. After the qualified tire repair professional has repaired your tire, they should clean the TPMS device with water to remove any sealant that may have come into contact with the device. After the repaired tire is replaced and inflated, the TPMS system can be reset and will resume operating as normal.”

RAV4 Tire Pressure Warning - New Tire Or New Tires
If you buy new tires and immediately get a tire pressure warning light check the pressure. Mistakes happen. Flats sometimes happen driving out of a tire shop. If you have checked the pressure and it is properly set, return to the retailer and let them know that the RAV4’s TPWS system has indicated a problem. If the retailer changed the valve stems the system may need to be re-initialized.

Be aware that some generations and styles of TPWS systems are sensitive to tire sizes. You should only use the exact size of tire your RAV4 came with. If you have mounted new wheels or a different size tire, the retailer who did the work should be able to explain to you how they will resolve the TPWS system.

RAV4 Tire Pressure Warning - Nitrogen Is Unnecessary
There are some dealers and shop that will suggest nitrogen as a solution to a TPWS problem in a RAV4. This is unfortunate. The claims that advocates of nitrogen make are unfounded by science or in real world applications (the author’s degree is in mechanical engineering. Ask the nitrogen seller about her science degree).

Furthermore, your Toyota was designed to work perfectly fine using compressed air. And it should. Does inflating an underinflated tire with nitrogen cause the TPWS light to go out. Of course it does. Just as inflating it with air will do. If you wish to waste money on nitrogen, feel free. Just know that the Toyota RAV4 doesn’t need it.

A TPWS system problem is always an annoyance, but for the most part, it is a feature that is there to help us in case a dangerous situation develops. Add air to your RAV4’s tires when temperatures begin to drop in early winter. Re-set it again in early summer. These are the best two practices you can have to avoid TPWS issues.

RAV4 Tire Pressure Frequently Asked Questions:
Q: Why is my tire pressure light on when my tires are fine?
A: This can be caused by a new tire, a defective sensor, or a problem with the system. Don’t assume the tires are fine. Check the pressure with a gauge.
Q: What is the tire pressure supposed to be for a RAV4?
It will be someplace between 30 and 40 psi. The correct pressure for every RAV4 is printed on the driver’s door jam
Q: Is it dangerous to drive with the tire pressure light on?
A: Yes, at least until you have checked the pressure with a tire pressure gauge to verify that the pressures are correctly set. Drive to a safe area as soon as practical and check the pressures when the TPWS light illuminates.
Q: Will TPMS light come on if tires are overinflated?
A: Yes, but it will have to be a significant overinflation, not a psi or two (or even five).

Resources List:
RAV4 Owner's Manual

John Goreham is a long-time New England Motor Press Association member and recovering engineer. Following his engineering program, John also completed a marketing program at Northeastern University and worked with automotive component manufacturers. In addition to Torque News, John's work has appeared in print in dozens of American newspapers and he provides reviews to many vehicle shopping sites. You can follow John on Twitter, and view his credentials at Linkedin

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