BMW 440i XDrive Gran Coupe Smells Like Gas

Diagnosing Fuel Odor Issues in Your BMW 440i xDrive Gran Coupe and Essential Safety Measures

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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
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40% chance it's the
Emissions Control System
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45% chance it's
Something else
The most common reasons a BMW 440i xDrive Gran Coupe 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 BMW 440i xDrive Gran Coupe 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.

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.

Troubleshooting Gas Smell in a BMW 440i xDrive Gran Coupe

When faced with a gas smell in your BMW 440i xDrive Gran Coupe, it's essential to adopt a systematic diagnostic approach. Begin by checking the gas cap, as a loose or damaged cap is often the simplest and most common culprit behind fuel odors. Ensure it is securely fastened and inspect for any signs of wear or damage. If the gas cap is in good condition, proceed to examine the fuel system, focusing on fuel lines and injectors for any visible leaks or deterioration. Next, investigate the emissions control system, as malfunctions here can also contribute to gas smells. If your vehicle falls within the recall range for faulty fuel pumps, it’s crucial to verify this and seek professional assistance if necessary. Should these initial checks not resolve the issue, consider consulting a qualified mechanic who can perform a comprehensive inspection using specialized diagnostic tools. This methodical approach not only helps in identifying the source of the gas smell but also ensures that you address the problem safely and effectively.

What Could Cause a Gas Smell in a BMW 440i xDrive Gran Coupe?

When a gas smell permeates your BMW 440i xDrive Gran Coupe, it’s crucial to identify the source to ensure safety and vehicle integrity. One of the most frequent culprits is a faulty gas cap, which can fail to create a proper seal, allowing fuel vapors to escape. Additionally, issues within the fuel system, such as leaking fuel injectors or damaged fuel lines, can lead to significant fuel leakage, resulting in a noticeable odor. The emissions control system is another area to investigate; leaks in components like the EVAP system or purge valve can also contribute to gas smells. Furthermore, fluid leaks from various sources, including ruptured hoses or gaskets, can emit strong odors that may be mistaken for gasoline. If you detect a gas smell, it’s essential to act quickly, as both minor and major issues can pose safety risks. For those inclined to DIY, a thorough inspection of these components can help pinpoint the problem, but consulting a qualified mechanic is advisable for a definitive diagnosis and repair.

What Should You Do If Your BMW 440i xDrive Gran Coupe Smells Like Gas?

If your BMW 440i xDrive Gran Coupe emits a gas smell, it’s crucial to act promptly to avoid serious safety hazards and costly repairs. Start by checking the gas cap, as a loose or damaged cap is a common culprit that can easily be fixed. Next, inspect the fuel system for leaks, particularly around the fuel injectors, as any signs of leakage can indicate a more significant problem that requires immediate attention. Additionally, don’t overlook the emissions control system; issues here can not only contribute to gas odors but also affect your vehicle's performance and compliance with environmental regulations. If you notice a burning smell alongside the gas odor, this could signal overheating or coolant leaks, which necessitate urgent monitoring and potential repairs. If the source of the smell remains elusive or if the odor persists, seeking a professional inspection is advisable to ensure your safety and the integrity of your vehicle. Remember, addressing these symptoms promptly can prevent further complications and ensure a safe driving experience.

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BMW 440i xDrive Gran Coupe: Why It Smells Like Gas