2017 Mercedes-Benz SL450 Smells Like Gas

Diagnosing Fuel Odor Issues in Your 2017 Mercedes-Benz SL450 and Essential Safety Precautions

Find Repair Location
Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
15% chance it's the
Gas Cap
0%
40% chance it's the
Emissions Control System
0%
45% chance it's
Something else
The most common reasons a 2017 Mercedes-Benz SL450 smells like gas are the gas cap, the fuel system, or the emissions control system.
  • Gas Cap: A loose or damaged gas cap can cause fuel vapors to escape, triggering the check engine light and potentially affecting fuel system pressure.
  • Emissions Control System: A faulty emissions control system can lead to increased hydrocarbon emissions and trigger the check engine light due to malfunctioning components like the EGR valve or O2 sensors.
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 2017 Mercedes-Benz SL450 smells like gas?

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.

A failing catalytic converter can cause a vehicle to fail emissions tests and turn on the check engine light. The exhaust might have an unusual smell. A restricted catalytic converter can result in a loss of engine power.

» LEARN MORE: How to tell if your catalytic converter is failing

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. The canister may also cause difficulty starting the engine, a rough idle, and poor fuel mileage.

When the fuel filter begins to clog, the engine suffers from fuel starvation. This will cause a significant reduction in power and may also cause a misfire. These conditions may be intermittent, or constant and worsen over time. As the issue progresses, the engine may being to stall immediately after starting, fail to start, hesitate under throttle, or stall at particular angles on hills.

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. A fuel tank leak may also cause difficulty starting the engine, a rough idle, and poor fuel mileage. When a fuel tank is simply corroded to the point of failure, the exterior tank condition rarely shows damage. The inside of the fuel tank will be rusted or corroded, and rust flakes or other debris may be floating in the fuel.

For most vehicles, the only symptom will be a check engine light or fuel tank filler cap light illuminating on the driver instrument cluster. This is to signal that there is an evaporative emissions (EVAP) leak. In some situations, the vehicle may take longer than normal to start, or, more rarely, the engine may not start at all. on-board diagnostic (OBD) trouble codes will refer to EVAP system failures such as a small or massive EVAP system leak. Lastly, the powertrain control module may notice a lean running condition, which could even lead to random and infrequent misfires.

What could be causing the gas smell in my 2017 Mercedes-Benz SL450, and what diagnostic steps should I take first?

When you notice a gas smell in your 2017 Mercedes-Benz SL450, it's important to take a systematic approach to diagnose the issue effectively. Begin by checking for fuel leaks, as even minor leaks in the fuel lines, tank, or injectors can produce a strong odor. Next, ensure that the fuel cap is securely fastened; a loose or damaged cap can allow fuel vapors to escape, contributing to the smell. If these initial checks do not reveal the source, inspect the exhaust system for any leaks or problems with the catalytic converter, as these can also lead to gas odors inside the vehicle. Additionally, evaluate the evaporative emissions control system, which is designed to prevent fuel vapors from escaping; a malfunction in this system can result in similar symptoms. If you are still unable to identify the source of the gas smell after these steps, it is advisable to consult a professional mechanic who can conduct a thorough diagnostic assessment. By following this structured diagnostic approach, you can effectively identify the cause of the gas smell and take the necessary steps to resolve it, ensuring both your safety and the proper functioning of your vehicle.

What could be causing a gas smell in my 2017 Mercedes-Benz SL450?

If you're detecting a gas smell in your 2017 Mercedes-Benz SL450, it's crucial to investigate the underlying causes to ensure both safety and vehicle performance. One of the most common culprits is a fuel leak, which can occur in various areas such as the fuel lines, fuel tank, or fuel injectors. Inspecting these components for any signs of leakage or damage is a good starting point. Additionally, a faulty fuel injector may also be responsible for the odor, as it can leak fuel into the engine compartment. Another area to check is the fuel tank itself; any cracks or holes can lead to fuel vapors escaping into the cabin. Don't overlook the fuel cap, as a loose or damaged cap can allow vapors to escape, contributing to the smell. Lastly, issues with the exhaust system, including leaks or problems with the catalytic converter, can also produce a gas odor. If you identify any of these issues during your inspection, it's advisable to consult a qualified mechanic for a thorough diagnosis and repair. Addressing these problems promptly will help maintain the safety and efficiency of your vehicle.

How urgent is it to address the gas smell in my 2017 Mercedes-Benz SL450?

Addressing a gas smell in your 2017 Mercedes-Benz SL450 is not just a matter of inconvenience; it is a pressing safety concern that demands immediate attention. Gas leaks pose a significant risk of fire or explosion, particularly in the confined space of a vehicle, where even a small spark can lead to catastrophic outcomes. Moreover, inhaling gas fumes can have serious health implications, causing symptoms such as dizziness, headaches, and nausea, which can escalate to more severe health issues with prolonged exposure. Ignoring this warning sign can also lead to further damage to your vehicle's components, resulting in costly repairs down the line. Therefore, it is crucial to take any gas smell seriously and address it promptly to safeguard both your health and the integrity of your vehicle.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.