2020 Mercedes-Benz CLA35 AMG Smells Like Gas

Troubleshooting Fuel Odor Issues in Your 2020 Mercedes-Benz CLA35 AMG and Essential Safety Tips

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Reviewed by
Devin Cabugcal
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 2020 Mercedes-Benz CLA35 AMG 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 2020 Mercedes-Benz CLA35 AMG 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.

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.

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 the potential causes of a gas smell in a 2020 Mercedes-Benz CLA35 AMG, and how should I diagnose the issue?

When faced with a gas smell in your 2020 Mercedes-Benz CLA35 AMG, it's essential to adopt a systematic diagnostic approach to identify the underlying issue. Start by inspecting for any visible fuel leaks around the fuel tank and lines, as these are often the most straightforward problems to detect. If no leaks are apparent, examine the fuel injectors for signs of malfunction, as a faulty injector can lead to fuel seeping into the engine compartment. Next, consider the evaporative emissions system; issues with components like the charcoal canister or purge valve can also produce a gas odor. Additionally, check the exhaust system for leaks, as these can allow exhaust fumes to enter the cabin, mimicking a gas smell. Lastly, be mindful of overfilling the gas tank during refueling, as this can lead to fuel spillage. If these initial checks do not reveal the source of the smell, utilizing a gas leak detector or an OBD-II scanner can provide further insights into potential issues. By following this structured approach, you can effectively diagnose and address the gas smell in your vehicle.

What could be causing a gas smell in my 2020 Mercedes-Benz CLA35 AMG?

If you're detecting a gas smell in your 2020 Mercedes-Benz CLA35 AMG, it's crucial to understand the common problems that could be at play. One of the primary culprits could be a fuel leak, which may stem from a compromised fuel injector, a damaged fuel line, or even a leaking fuel tank. This situation is not only concerning but also poses a significant safety risk, necessitating immediate attention. Another frequent issue is a faulty fuel cap; if it's loose or damaged, it can allow fuel vapors to escape, leading to that unmistakable gas odor. Additionally, problems within the exhaust system, such as leaks or a malfunctioning catalytic converter, can also contribute to the smell infiltrating the cabin. Engine-related issues, including malfunctioning sensors or fuel injection problems, may further exacerbate the situation, making it wise to have the engine inspected by a professional. Lastly, consider the evaporative emissions system, which is designed to manage fuel vapors; any malfunction here can also result in a gas smell. Addressing these potential issues promptly is essential for both safety and vehicle performance, so if you're unsure, consulting a qualified mechanic is always a prudent step.

How urgent is it to address a gas smell in a 2020 Mercedes-Benz CLA35 AMG?

When you detect a gas smell in your 2020 Mercedes-Benz CLA35 AMG, it is imperative to act swiftly due to the serious safety risks involved. Gasoline is not only highly flammable but also poses a significant threat of fire or explosion if a leak is present. Beyond the immediate danger, a gas smell often indicates a leak in the fuel system, which can compromise your vehicle's performance and fuel efficiency. Additionally, inhaling gasoline fumes can lead to health issues such as headaches, dizziness, and nausea, making it essential to prioritize your well-being. Ignoring this warning sign can result in further damage to your vehicle, leading to costly repairs down the line. Therefore, it is crucial to have the issue inspected and resolved by a qualified mechanic without delay to ensure both your safety and the longevity of your car.

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