2009 Smart Fortwo Tire Pressure Warning Light Stays On

Resolve Tire Pressure Warning Light in 2009 Smart Fortwo

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Reviewed by
Aisha
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Tire Leaking Air
0%
30% chance it's the
Wheel Leaking Air
0%
15% chance it's the
Tire Pressure Monitoring System
0%
15% chance it's
Something else
The most common reasons a 2009 Smart Fortwo tire pressure warning light stays on are a leaking tire, a wheel that no longer holds air, or a faulty tire pressure monitoring system.
  • Tire Leaking Air: A puncture, valve stem issue, or rim damage can cause a tire to leak air, leading to loss of pressure.
  • Wheel Leaking Air: A puncture or damage to the tire or rim can cause air to leak, resulting in a loss of tire pressure.
  • Tire Pressure Monitoring System: A malfunctioning tire pressure monitoring system can be caused by faulty sensors or a dead battery in the sensor units.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2009 Smart Fortwo tire pressure warning light stays on?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When a tire pressure monitoring sensor fails, the tire pressure monitoring system control module will recognize a loss in communication and turn on the warning lamp which indicates the failure. This is most often the case. However, the tire pressure monitoring sensor may also fail by reporting incorrect tire pressures. This could cause a flat tire to go unrecognized, or a properly inflated tire to signal a low or high tire pressure warning.

When a relearn is needed, for any reason, the TPMS warning light will illuminate, and many vehicles will display a message relating to the TPMS system being inoperative or loosing communication. It is important to keep a watchful eye on tire pressures when this system is having issues because there is no warning available for underinflation or overinflation of the tires.

Wheels offer very few symptoms, but these symptoms should never be ignored. Visible cracks on the wheels may appear, especially after hitting a large bump, Most often, this will also be accompanied by loss of air from the tire on that wheel. Also, vibration in the steering wheel is very common when the tire is out of balance, and improper wheel nuts or bolts can cause creaking and popping noises to develop. Again, there are very few symptoms, but they should not be ignored.

The only symptoms of a TPMS control module failure are failing to alert the driver of underinflation or overinflation of one or more tires, failure to communicate with the body control module or TPMS sensors, or erroneously reporting incorrect tire pressure.

The only symptoms requiring diagnosis for the tire pressure monitoring system warning lamp is if the warning lamp has illuminated while the tires have correct air pressure, or if the air pressure for the tires is out of specification and the warning lamp is off. This is because the overwhelming majority of cases where the TPMS lamp illuminates is due to the change in ambient temperature.

What are the initial steps to diagnose a persistent tire pressure warning light on a 2009 Smart Fortwo?

When faced with a persistent tire pressure warning light on your 2009 Smart Fortwo, the first step is to check the tire pressure in all four tires, ensuring they are inflated to the manufacturer's recommended levels, as low pressure is a frequent culprit. Next, inspect each tire for any visible damage, such as punctures or bulges, which could indicate a leak. If the tires appear to be in good condition, consider resetting the tire pressure monitoring system according to the vehicle's manual, as this can sometimes resolve the issue. Additionally, examine the tire pressure sensors for any signs of damage or corrosion, as malfunctioning sensors can trigger the warning light. If, after these steps, the warning light remains illuminated, it may be time to consult a professional mechanic for a more thorough diagnosis and repair. By following this methodical approach, you can effectively troubleshoot the issue and potentially save on repair costs.

What could cause the tire pressure warning light to remain on in a 2009 Smart Fortwo?

When the tire pressure warning light remains on in a 2009 Smart Fortwo, it can indicate several underlying issues that are manageable for DIY enthusiasts. The most common reason is low tire pressure; therefore, the first step is to check each tire and inflate them to the recommended levels, which is a simple yet effective solution. If the tire pressure is adequate, the next possibility is a faulty tire pressure sensor that may need replacement. Additionally, the sensors could require recalibration to ensure they are functioning correctly, a process that can usually be followed using the vehicle's manual. It's also important to consider potential electrical problems within the tire pressure monitoring system, so inspecting the wiring and connections for any faults is a wise move. Lastly, a system reset can sometimes resolve false alerts, allowing the warning light to turn off. By methodically addressing these common issues, you can troubleshoot and potentially fix the tire pressure warning light problem in your Smart Fortwo.

What should I do if the tire pressure warning light stays on in my 2009 Smart Fortwo?

If the tire pressure warning light stays on in your 2009 Smart Fortwo, it is essential to act quickly to avoid potential safety hazards and vehicle damage. Neglecting this warning can lead to unsafe driving conditions, increased tire wear, and even blowouts, which pose serious risks on the road. Begin by checking the tire pressure in all four tires, including the spare, ensuring they are inflated to the levels specified in your vehicle's manual. If you find any tires are underinflated, use a tire pressure gauge to inflate them to the correct pressure. Additionally, inspect each tire for any visible damage, such as punctures or cuts, which could be causing a loss of pressure. If you identify any damage, it is crucial to repair or replace the tire to prevent further issues. After adjusting the tire pressure, refer to your vehicle's manual to determine if a manual reset of the tire pressure monitoring system is required. Should the warning light remain illuminated despite these measures, it may indicate a more serious problem with the monitoring system itself, necessitating a visit to a mechanic or dealership for further diagnosis. By addressing the tire pressure warning light promptly, you not only enhance your vehicle's performance but also ensure your safety and that of others on the road.

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2009 Smart Fortwo Tire Pressure Warning Light Solutions