2021 Mercedes-Benz CLA35 AMG Smells Like Gas

Common Causes of Fuel Odors in Your 2021 Mercedes-Benz CLA35 AMG and How to Address Them

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Reviewed by
Aisha
Written by RepairPal Car Genius
Updated January 14, 2025
0%
15% chance it's the
Gas Cap
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40% chance it's the
Emissions Control System
0%
45% chance it's
Something else
The most common reasons a 2021 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 2021 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 are the potential causes of a gas smell in a 2021 Mercedes-Benz CLA35 AMG, and how should I diagnose the issue?

When faced with a gas smell in your 2021 Mercedes-Benz CLA35 AMG, it's essential to adopt a systematic diagnostic approach to identify the underlying issue. Start with a thorough visual inspection of the fuel system, focusing on areas such as the fuel lines, injectors, and tank for any signs of leaks or damage. If you notice any fuel pooling or wet spots, this could indicate a fuel leak that needs immediate attention. Next, check for any warning lights on your dashboard, particularly the check engine light, as this can provide valuable diagnostic codes when scanned with an OBD-II tool. If the light is illuminated, it may point to specific issues like a faulty fuel injector or problems within the evaporative emissions system. Additionally, consider whether you've recently overfilled the gas tank, as this can lead to fuel spillage and odors. If these initial checks do not reveal the source of the smell, it may be time to investigate more complex components, such as the exhaust system for leaks or the evaporative emissions system for malfunctions. If you're still unable to pinpoint the problem, seeking assistance from a qualified mechanic is advisable to ensure a comprehensive diagnosis and safe resolution of the issue.

What could be causing the gas smell in my 2021 Mercedes-Benz CLA35 AMG?

If you're detecting a gas smell in your 2021 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 damaged fuel line, a leaking fuel injector, or even a faulty fuel tank cap. These issues can lead to fuel escaping into the engine compartment or under the vehicle, creating a noticeable odor. Another potential source is the evaporative emissions system, designed to prevent fuel vapors from escaping into the atmosphere. If this system malfunctions, it can result in a gas smell inside the cabin. Additionally, consider the exhaust system; a leak from components like the exhaust manifold or catalytic converter can allow exhaust gases to enter the vehicle, mimicking a fuel odor. Lastly, overfilling your gas tank can lead to fuel spillage, which is a simple yet often overlooked cause of a gas smell. For those inclined to DIY, inspecting these areas can help identify the source of the problem, but always prioritize safety and consult a professional if you're uncertain about any repairs.

How urgent is it to address the gas smell in my 2021 Mercedes-Benz CLA35 AMG?

Addressing a gas smell in your 2021 Mercedes-Benz CLA35 AMG is not just a matter of convenience; it is an urgent safety concern that should not be overlooked. The presence of gasoline fumes can indicate a fuel leak, which poses a significant risk of fire or explosion, endangering both you and others on the road. Additionally, inhaling these fumes can lead to serious health issues, including headaches, dizziness, and nausea, which can impair your ability to drive safely. Beyond safety and health, neglecting this issue can result in costly damage to your vehicle's engine or fuel system, leading to more extensive repairs down the line. Therefore, it is crucial to take immediate action by consulting a professional mechanic to diagnose and resolve the problem, ensuring your safety and the longevity of your vehicle.

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