Can Fix-A-Flat Damage Tire Pressure Monitor Sensors?

Flat tire
Products like Fix-A-Flat get you back on the road quick and easy, but there can be complications with the TPMS. vitapix/iStock

Question: Can fix-a-flat emergency tire inflating sprays ruin TPMS sensors?

I had a tire go flat the other day, and I used one of those fix-a-flat cans instead of putting on the spare or having the car towed. It worked just fine, but then I had the tire fixed and the guys at the tire store told me that I ruined my “TPMS sensor” and that I would need a new one. Can fix-a-flat really ruin a sensor like that?

Answer:

The issue of tire pressure monitoring system (TPMS) sensors and products like Fix-A-Flat is somewhat contentious, and it’s impossible to make a judgment on any specific situation without actually having access to the sensor in question.

Conventional wisdom has said for a while that products like Fix-A-Flat and TPMS sensors don’t mix, but expert opinions have shifted in recent years, so while it is possible that your sensor could have been damaged by using a product like Fix-A-Flat, the situation is a little more complicated.

This all assumes that the TPMS sensors in question are the kind that is located inside the tire. Most OEM TPMS sensors are built into the valve stem, with the delicate sensor portion located inside the tire, but there are other systems where the sensor is in the cap. When a TMPS sensor is located in the cap, it can't be damaged by anything that's inside the tire at any rate.

Truth and Rumors About Fix-A-Flat Emergency Tire Repairs

Fix-A-Flat is a brand name that people tend to use in reference to all products in the same range, in the same way, that people will call generic tissue paper Kleenex, refer to a photocopy as a Xerox, or Google for information on the Internet. That said, products like Fix-A-Flat, Slime, and other emergency tire sealers and inflators all work on the same general principle of injecting a sealant and then filling the tire with air or some other gas.

There are two major types of these emergency tire repair products. The first contains both a sealant and some type of compressed gas, typically in a cannister. When this type of product is used, the tire is both sealed and inflated to some degree. The other type consists of a sealant in addition to a traditional air pump. The sealant seals the leak from the inside out, and the pump is used to fill the tire to a safe level.

There are also two persistent rumors that surround these types of products. The first is that they can cause fires or explosions, and the other is that they can damage tires, rims, and TPMS sensors.

Fix-A-Flat is the type that combines a sealant and compressed gas into a single dispenser. At one point, the gas was combustible, which is where the rumor that Fix-A-Flat causes fires or explosions came from. The idea was that if an emergency tire repair product uses a flammable gas, and dispenses that flammable gas into a tire, it could catch on fire during the repair.

Since most tire repairs involve removing the foreign object that punctured the tire and then reaming out the hole with a special metal tool, the idea that the tool rubbing against the steel belts in the tire could create a spark, and ignite the flammable material left in the tire from an emergency Fix-A-Flat application was very real.

Today, Fix-A-Flat uses non-flammable materials, but the rumor persists, and it’s always possible that someone, somewhere, is still manufacturing an emergency tire product that uses a flammable propellant, or that someone still has an ancient can of new old stock Fix-A-Flat laying around that still works.

The other rumor, that products like Fix-A-Flat and Slime damage TPMS sensors, tires, and rims, persists, and there is both some truth and likely some exaggeration or misunderstanding behind it.

Can Fix-A-Flat Damage TPMS Sensors, Tires, and Rims?

If you run an image search for rims or TPMS sensors that were damaged by Fix-A-Flat, get ready to view some tire gore.

It’s unclear whether this type of damage is actually caused by modern Fix-A-Flat though, by older versions, or by similar products in the same range. It’s also unclear as to how long it takes for this type of corrosion and other damage to occur.

For instance, Fix-A-Flat claims that its product is safe for use with TPMS, but with the caveat that the user should have their tire fixed, cleaned, and inspected as soon as possible. So while the product, as currently formulated, is designed to be safe for use with TPMS sensors, driving around for an extended period of time without having the tire cleaned and fixed may have unforeseen consequences.

Related to this issue is the fact that all emergency tire repair products leave some form of residue inside the tire that has to be cleaned out. This is an issue because most tire repairs that involve some type of puncture can be repaired either on the vehicle or at least without removing the tire from the rim. The typical procedure involves removing the foreign object, reaming out the hole with a specialty tool, and then installing a plug.

When you inject a product like Fix-A-Flat or Slime into your tire, the tire has to be removed from the rim, and cleaned, before it can be repaired. If the puncture is simply plugged, the sealant will remain in the tire. This can make difficult or impossible to balance a tire, and it can also render a TPMS sensor inoperable or inaccurate.

Cleaning Tires and TPMS Sensors After Using Fix-A-Flat

When you take a tire in for repairs after using a product like Fix-A-Flat or Slime, it’s important to let the shop know that you used one of these products.

In the past, it was extremely important so that they would be able to avoid igniting flammable materials left in the tire, but it’s still important today so that the mechanic will know what they are dealing with.

Rather than simply plugging a damaged tire that was temporarily repaired with Fix-A-Flat, the manufacturers of Fix-A-Flat and other similar products recommend that the interior of the tire and rim be cleaned with water before any repairs take place. If the vehicle has a TPMS system, then it’s also important for the sensors to be cleaned at this time.

In most cases, cleaning a TPMS sensor before repairing and mounting the damaged tire will return it to useful service. In fact, Consumer Reports ran tests on a number of different types of emergency tire repair products and vehicles, and they found that none of these products damaged the TPMS sensors if the sensors were cleaned after the product was used.

The bottom line is that if your TPMS system starts malfunctioning after a product like Fix-A-Flat was used, there are several different possible explanations. The TPMS sensor could have been damaged, particularly if the vehicle was driven for an extended period of time, or the shop could have neglected to clean the sensor. The latter possibility is especially likely if the shop wasn’t alerted to the fact that Fix-A-Flat was used, which is why it’s especially important to bring that up when a vehicle is equipped with a TPMS system.