2020 Mercedes-Benz SL450 Tire Pressure Warning Light Stays On

Resolve Tire Pressure Warning Light in 2020 Mercedes-Benz SL450: Causes and Solutions

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Reviewed by
Bo Fader
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 2020 Mercedes-Benz SL450 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 2020 Mercedes-Benz SL450 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 2020 Mercedes-Benz SL450?

When faced with a persistent tire pressure warning light on your 2020 Mercedes-Benz SL450, the first step is to check the tire pressure in all four tires, ensuring they are inflated to the manufacturer's recommended levels. This is crucial, as low tire pressure is a frequent culprit behind such warning lights. Next, visually inspect each tire for any signs of damage, such as punctures, cuts, or bulges, which could indicate a more serious issue. If the tire pressure appears correct and no visible damage is found, consider resetting the tire pressure monitoring system as outlined in your vehicle's manual; this can sometimes clear false warnings. To ensure accuracy, use a reliable tire pressure gauge to double-check the readings. If the warning light remains illuminated despite these efforts, it may point to a faulty tire pressure sensor that requires replacement. By systematically following these steps, you can effectively diagnose and address the tire pressure warning light issue, potentially saving time and money on professional repairs.

What could be causing the tire pressure warning light to remain on in a 2020 Mercedes-Benz SL450?

When the tire pressure warning light remains illuminated in your 2020 Mercedes-Benz SL450, it’s crucial to understand the common problems that could be causing this issue. One of the primary culprits is low tire pressure, which can easily be checked with a tire pressure gauge. Ensure that all tires are inflated to the manufacturer’s recommended levels, as even a slight drop can trigger the warning light. If the tire pressure is adequate, the problem may lie with the tire pressure monitoring system (TPMS) sensor itself. A faulty sensor can lead to incorrect readings, necessitating either a replacement or recalibration. Additionally, consider the possibility of depleted batteries in the tire pressure sensors, which can also cause malfunctions. Extreme temperature fluctuations can affect tire pressure, so it’s wise to adjust your tire pressure accordingly during seasonal changes. If these steps do not resolve the issue, a malfunction within the TPMS system may be at play, requiring a diagnostic scan to pinpoint the problem. Addressing these common issues not only enhances your vehicle's safety but also ensures optimal performance on the road.

How urgent is it to address the tire pressure warning light on my 2020 Mercedes-Benz SL450?

Addressing the tire pressure warning light on your 2020 Mercedes-Benz SL450 is not just a matter of convenience; it is a critical safety concern that requires immediate attention. Ignoring this warning can lead to serious consequences, including compromised vehicle handling and increased risk of accidents. Low tire pressure can significantly affect your car's stability, making it harder to control, especially in emergency situations. Additionally, neglecting to check and maintain proper tire pressure can result in uneven tire wear, which not only shortens the lifespan of your tires but can also lead to costly replacements. Furthermore, underinflated tires can decrease your vehicle's fuel efficiency, leading to higher fuel costs over time. For DIY enthusiasts, regularly checking your tire pressure is a straightforward task that can be done with a simple tire gauge. By taking the time to address the warning light promptly, you ensure your safety on the road, enhance your vehicle's performance, and save money in the long run.

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