2017 GMC Sierra 2500 HD Smells Like Gas

Addressing Gas Smells in Your 2017 GMC Sierra 2500 HD Safely

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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 GMC Sierra 2500 HD 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 GMC Sierra 2500 HD 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

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 steps should I take to diagnose the gas smell in my 2017 GMC Sierra 2500 HD?

To effectively diagnose the gas smell in your 2017 GMC Sierra 2500 HD, start with a systematic approach that prioritizes safety and thoroughness. Begin by checking for visible leaks under the vehicle, as this is often the simplest and quickest way to identify a problem. Look for any signs of gasoline pooling or wet spots around the fuel tank and fuel lines. Next, inspect the fuel lines and connections for any damage, corrosion, or loose fittings that could be contributing to the odor. Don’t overlook the fuel tank itself; any cracks or punctures can lead to significant fuel leaks. Additionally, examine the fuel injectors, as a malfunctioning injector can also emit a gas smell. It’s important to assess the evaporative emissions control system, as issues here can lead to fuel vapors escaping. Lastly, check the exhaust system for leaks, which can sometimes mimic a gas smell inside the cabin. If these steps do not reveal the source of the odor, or if you feel uncomfortable performing these checks, it’s wise to consult a qualified mechanic who can provide a comprehensive diagnosis. By following this methodical approach, you can effectively pinpoint the issue and take the necessary steps to resolve it.

What are the common problems that could cause a gas smell in a 2017 GMC Sierra 2500 HD?

When you notice a gas smell in your 2017 GMC Sierra 2500 HD, it's essential to investigate the potential causes to ensure your safety and the vehicle's reliability. A leaking fuel injector is often a primary suspect, as it can allow fuel to escape and create a strong odor. Additionally, a faulty fuel pressure regulator may fail to maintain the necessary pressure, leading to fuel leaks. Cracks in the fuel tank can also release fumes into the cabin, while damaged fuel lines can exacerbate the issue by allowing fuel to seep out. Furthermore, problems with the evaporative emissions control system, including a malfunctioning charcoal canister, can contribute to the gas smell. It's vital to address these issues promptly; therefore, if you detect a gas odor, seeking a professional mechanic's expertise for a thorough inspection is highly recommended to identify and rectify the problem effectively.

How urgent is it to address the gas smell in my 2017 GMC Sierra 2500 HD?

When you detect a gas smell in your 2017 GMC Sierra 2500 HD, it is essential to act quickly due to the serious safety risks involved. Gasoline leaks not only pose a significant fire hazard but can also lead to harmful health effects from inhaling fumes. If you are considering a DIY approach, start by inspecting the fuel lines, connections, and the fuel tank for any visible signs of leaks or damage. Ensure that your vehicle is parked in a well-ventilated area and take necessary precautions, such as wearing gloves and a mask, to protect yourself from harmful vapors. If you identify any issues, it is crucial to address them immediately, as neglecting these symptoms can lead to more severe problems, including costly repairs and compromised vehicle performance. While some minor repairs may be manageable on your own, do not hesitate to consult a professional mechanic for a thorough inspection and repair to ensure your safety and the reliability of your GMC Sierra.

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2017 GMC Sierra 2500 HD Gas Smell Causes & Solutions