Will Low Tire Pressure Sensor Fail Inspection? What You Need To Know

Having low tire pressure can be a safety hazard on the road. But will it automatically cause you to fail a vehicle inspection? The answer depends on the specifics of your state’s inspection regulations. In this comprehensive guide, we’ll cover everything you need to know about low tire pressure sensors and how they factor into passing or failing a vehicle inspection.

Here’s a quick answer: Whether a faulty tire pressure monitoring system (TPMS) can cause an inspection failure depends on individual state regulations. Around 12 states mandate inspections of TPMS functionality and may fail vehicles with malfunctioning TPMS sensors or warning lights. In other states, TPMS issues alone generally will not lead to automatic inspection failure.

What is a Tire Pressure Monitoring System (TPMS)?

A tire pressure monitoring system, or TPMS, is an electronic system designed to monitor the air pressure inside your tires. It consists of sensors attached to each tire’s valve stem, which measure pressure levels and transmit this data to a central computer.

The TPMS computer then alerts the driver if any tire pressure falls below the vehicle manufacturer’s recommended level, typically by illuminating a low tire pressure warning light on the dashboard. This gives you time to address the issue before it becomes a safety concern.

TPMS has been mandatory standard equipment in all light-duty vehicles in the U.S. since 2007. It provides an important safety net against the dangers of underinflated tires, such as:

  • Reduced braking performance and control
  • Premature tire wear
  • Increased risk of blowouts
  • Poorer fuel economy

TPMS Inspection Regulations By State

Whether a faulty TPMS light or sensor can cause you to fail inspection depends entirely on your state’s specific vehicle inspection regulations.

States Where TPMS Issues May Lead to Inspection Failure

There are currently around a dozen states that explicitly include TPMS in their safety or emissions inspection requirements. If your vehicle’s TPMS system is found to be defective or non-functional during inspection in these states, you will fail:

  • Alaska
  • Utah
  • Missouri
  • Pennsylvania
  • Maine
  • New Hampshire
  • Louisiana
  • Vermont
  • West Virginia
  • New York
  • Virginia
  • North Carolina
  • Texas

For example, the Texas Department of Public Safety states that “the TPMS system must be maintained and fully operational” to pass inspection. Most other states with TPMS inspection rules have similar language.

States Where TPMS Issues Do Not Lead to Inspection Failure

In the majority of states without TPMS-specific inspection guidelines, a problem with your tire pressure sensors alone will not cause you to fail safety or emissions testing.

However, the inspecting mechanic may still point out the issue and recommend you repair your TPMS system for optimal safety. Or, if one or more tires is found to be significantly underinflated during the inspection, you may fail based on the tire issue rather than the TPMS problem itself.

Will Driving With TPMS Warning Light On Fail Inspection?

If your TPMS system’s warning light is illuminated when you bring your vehicle in for inspection, the outcome depends on your state’s regulations:

  • In states that do not inspect TPMS functionality, the warning light alone will not lead to automatic failure. As long as your actual tire pressures are within safe limits.
  • In states that require TPMS to be fully operational, the illuminated TPMS light is considered grounds for inspection failure. Even if your tire inflation levels are satisfactory.

So before your next inspection, remember to reset your TPMS warning light if needed. This typically involves adding air to tires until the light turns off, then pressing a reset button. Consult your vehicle owner’s manual for the proper reset procedure.

Driving with the TPMS light on can technically be illegal in some states that include TPMS in periodic inspections.

Will Low Tire Pressure Alone Fail Inspection?

While issues with the TPMS system itself may or may not cause inspection failure depending on your state, all states will fail an inspection if one or more of your tires are found to be significantly underinflated.

Tire pressure minimums can vary between states. For reference, the recommended cold tire pressure levels for a typical passenger vehicle are around:

  • 30-35 PSI for passenger car tires
  • 50-80 PSI for light truck tires

Driving on extremely underinflated tires is dangerous and will almost certainly lead to inspection failure in any state.

What if Tire Pressure is Borderline Low?

If your tire pressure is slightly below the recommended level, but not drastically low, the outcome is more nuanced:

  • In states that do not focus on TPMS during inspection, you may pass as long as the mechanic judges your tires to be safe for the road.
  • In states that inspect TPMS functionality, even mildly underinflated tires that trigger the warning light could lead to failure.

To maximize your chances of passing inspection anywhere, fill your tires to the vehicle manufacturer’s specifications, found in your owner’s manual or on a sticker inside the driver’s side door jamb. Investing in your own portable tire pressure gauge can help you accurately maintain proper inflation.

Will a Faulty TPMS Fail an Emissions Test?

Problems with your vehicle’s TPMS system, warning light, or tire pressures will not cause you to fail a smog check or emissions inspection in any state.

Emissions tests are focused strictly on analyzing your vehicle’s exhaust gases, not safety equipment like TPMS. As long as your engine is running properly and producing acceptable emissions levels, you can pass an emissions test regardless of TPMS-related issues.

However, if your check engine light is on due to problems that could impact emissions, such as an ignition system malfunction, that would lead to emissions test failure in most states. Diagnose and repair the underlying issue before your next inspection.

Maintaining Your TPMS for Inspection Success

To maximize your chances of sailing through your next vehicle inspection, make tire pressure monitoring system maintenance part of your regular service routine:

  • Check tire pressures monthly: Use an accurate gauge to check inflation levels when tires are cold. Top up any underinflated tires to meet your vehicle’s recommended PSI.
  • Perform TPMS reset after tire pressure adjustments: Once all tires are properly inflated, conduct the TPMS reset procedure so the warning light turns off.
  • Replace TPMS sensors as needed: TPMS sensor batteries last 5-10 years typically. Replace any dead sensors immediately so the system remains fully functional.
  • Repair TPMS malfunctions promptly: If the TPMS light stays on despite properly inflated tires, have the system diagnosed and repaired by a professional.

With some preventative maintenance and awareness of your state’s inspection regulations, your vehicle’s tire pressure monitoring system shouldn’t stand in the way of passing vehicle safety or emissions testing. Maintaining proper tire pressures also helps keep you and your passengers as safe as possible out on the roads.

Frequently Asked Questions about TPMS and Inspections

Do I need functioning TPMS to pass inspection in my state?

It depends on your state’s inspection rules. Around 12 states require TPMS to be fully operational to pass. In other states, TPMS issues alone won’t lead to inspection failure.

How can I tell if my TPMS system is malfunctioning?

If the low tire pressure warning light stays on, even with properly inflated tires, it likely indicates a TPMS problem. Individual dead sensors may also trigger a TPMS malfunction.

Will a faulty TPMS sensor cause my car to fail emissions testing?

No, emissions tests only analyze the exhaust gases from your engine. TPMS does not impact emissions, so issues will not cause a smog check failure.

Do I need to reset my TPMS warning light before inspection?

In states that inspect TPMS, it’s a good idea to reset the light if needed. This involves topping off tire pressures and using the TPMS reset function. A lit warning light could lead to failure in some states.

Can I pass inspection if one of my tires is slightly underinflated?

It depends on local inspection rules and the judgment of the mechanic. Significantly underinflated tires will definitely fail, while mildly low tires may pass if deemed safe to drive.

How do I properly maintain my TMPS system?

Check tire pressures monthly, perform TPMS resets after adjusting pressure, replace dead sensors promptly, and repair any TPMS malfunctions as soon as possible. Proper maintenance will keep your system functioning optimally.

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