2021 Honda Accord Air Filter: Your Complete DIY Guide to Replacement & Maintenance

Replacing the cabin and engine air filters on your 2021 Honda Accord is a simple, inexpensive, yet crucial DIY maintenance task that significantly improves your driving experience, protects your engine, enhances cabin air quality, and helps maintain fuel efficiency. Neglecting these filters can lead to reduced performance, unpleasant odors, higher repair costs, and unnecessary strain on critical components. This comprehensive guide provides everything you need to confidently replace both filters yourself in under 30 minutes, saving you money at the dealership service center.

Understanding the Two Vital Filters in Your 2021 Honda Accord

Your Accord relies on two distinct filters, each performing a critical but separate function:

1. Cabin Air Filter (Often called the "Pollen Filter"):

   • Location: Behind the glove compartment.
   • Function: Cleans the air entering the passenger compartment through the heating, ventilation, and air conditioning (HVAC) system. It traps dust, pollen, mold spores, allergens, road debris, and pollutants before this air blows out your vents. A clean filter ensures better air quality for you and your passengers and maintains proper airflow from the HVAC system.
   • Replacement Frequency: Honda typically recommends inspecting it every 15,000-20,000 miles or once a year, whichever comes first. However, if you drive in dusty areas, encounter heavy pollen seasons, or notice reduced airflow or odors from the vents, replace it more often (potentially every 10,000-12,000 miles). Visually inspecting it twice a year is good practice.

2. Engine Air Filter:

   • Location: Inside a rectangular air filter box, usually found on the right (passenger) side of the engine compartment. An intake tube connects the box to the engine's throttle body.
   • Function: Cleans the air entering your engine for combustion. It traps dirt, dust, leaves, bugs, sand, and other airborne debris before they enter the sensitive engine cylinders. Clean air is essential for efficient combustion, engine longevity, peak performance, and optimal fuel economy.
   • Replacement Frequency: Honda's official recommendation is every 30,000 miles under normal driving conditions. However, severe driving conditions (like frequent stop-and-go traffic, heavy traffic in hot weather, dusty/sandy roads, repeated short trips under 5 miles, or mountainous terrain) warrant replacement every 15,000 miles. Inspect it at every oil change.

Precise Cabin Air Filter Location & Replacement Steps (2021 Accord)

1. Prepare Your Car: Park on a level surface, engage the parking brake, and remove the key from the ignition. No tools are required except possibly a screwdriver for specific clips.
2. Empty Glove Box: Remove all contents from your glove compartment.
3. Open Glove Box & Release Stoppers: Pinch or push in the sides of the glove compartment to clear the stopper arms, allowing the glove box to drop down lower than usual (you might need to depress small tabs near the hinge points on the sides of the glove box interior).
4. Locate the Cabin Filter Housing: Behind the lowered glove box, you will see a rectangular or square plastic cover panel with tabs or a screw on the side facing the passenger seat.
5. Remove Filter Cover: There are common variations:
   • Pinch-Tab Version: Push inwards on the plastic tabs located on the left and/or right sides of the cover while simultaneously pulling the cover towards you. It should detach.
   • Screw Version (Less Common): Use a Phillips head screwdriver to carefully remove any screws securing the side panel. Pull the panel straight out.
6. Remove Old Filter: Slide out the existing cabin air filter. Note its orientation – it usually has an airflow direction arrow printed on the frame. This arrow typically points towards the vehicle’s floor.
7. Inspect the Old Filter: Hold it up to a light source. If it looks very dark, caked with debris, or blocked, replacement is definitely needed.
8. Clean Housing (Optional but Recommended): Use a vacuum cleaner hose attachment or a microfiber cloth to wipe away loose debris inside the filter housing cavity. Avoid introducing liquid cleaners.
9. Install New Filter: Take your new Honda cabin air filter (e.g., Honda Genuine Part # 80292-TBA-A11, or a high-quality replacement like FRAM Fresh Breeze CF11734 or Bosch CA11734). Match the airflow arrow direction exactly to the one on your old filter – pointing DOWNWARDS, towards the floor. Slide the filter completely into the housing until it seats firmly.
10. Reinstall Filter Cover: Align the cover panel back into its position. For pinch tabs, push it firmly until all tabs snap securely into place. If it had screws, carefully re-tighten the screw snugly by hand – do not overtighten and risk stripping the plastic threads.
11. Reinstall Glove Box: Lift the glove box back into its normal position, ensuring the stopper arms align correctly. It should close smoothly.

Precise Engine Air Filter Location & Replacement Steps (2021 Accord)

1. Safety First: Park on a level surface, engage the parking brake, and turn off the engine. Allow the engine to cool if recently driven. Wear safety glasses for eye protection. Locate the engine air filter box – a black plastic rectangular housing on the right (passenger) side of the engine bay near the front windshield corner. The large ribbed intake tube connects to it.
2. Open Air Filter Box:
   • Release the metal clamps securing the top half of the air box. You may find one or two clamps. Slide the clamp(s) backwards or sideways to release tension; they don't need to be removed completely. Some clamps require pressing a small tab to unlock them before sliding.
   • Carefully lift the top cover of the air box straight up. There might be a small locking tab at the front or sides; gently disengage it. Do not pull on the intake tube or attached electrical wiring harness clips/sensors.
3. Remove Old Engine Air Filter: Lift out the old rectangular filter element. Inspect it visually. If the pleats are heavily coated in dirt or debris, or look very dark overall, replacing it is necessary.
4. Clean the Filter Box: Use a vacuum cleaner hose attachment to remove any large debris from the bottom half of the filter box. Carefully wipe any sticky residue with a clean, dry rag – be extremely careful not to let any debris fall into the opening leading towards the engine. Never use compressed air for cleaning near the open intake.
5. Install New Filter: Ensure your replacement engine air filter is clean and correct for your engine (most 1.5L Turbo and 2.0L Turbo engines use the same filter size, e.g., Honda Genuine # 17220-5B0-A01, Fram CA12080, WIX WA10899, or K&N E-9209 for a performance washable option). Drop the new filter into the bottom housing, ensuring it sits flat and the rubber sealing gasket is properly seated all around the perimeter. Double-check that no gasket is pinched or rolled under. The filter element itself might not have an airflow direction arrow since orientation is fixed by the box shape.
6. Reassemble the Box: Lower the top cover back onto the bottom housing. Ensure the cover sits flush and the rubber gasket from the bottom housing mates cleanly with the cover.
7. Re-secure Clamps: Slide the metal retaining clamp(s) back to their locked position over the housing lips. Ensure they are tight and firmly holding the two halves together, providing a solid seal.

Selecting the Best Filters for Your 2021 Honda Accord

• Genuine Honda Filters: While slightly more expensive ($20-$40), these parts (Cabin #80292-TBA-A11, Engine #17220-5B0-A01) are designed and tested specifically for optimal fit, flow, and filtration performance in your Accord. They ensure compatibility and consistent OEM quality. Recommended for owners prioritizing guaranteed performance and minimal risk.
• High-Quality Aftermarket Brands:
  • Premium Value Options: Brands like Fram (Ultra Synthetic cabin, Tough Guard engine), Bosch (Cabin+), or WIX offer excellent filtration and value (often $10-$25). Their products frequently meet or exceed OEM specifications and offer a good balance.
  • Washable Performance Filters (Engine Only): K&N (E-9209) is the major player here. These reusable cotton-gauze filters can offer slightly less restriction when clean, possibly allowing a minuscule performance gain. However, they require regular cleaning/oiling kits (every 50,000 miles). Crucial Notes: Over-oiling can damage the mass airflow sensor (MAF). They may allow finer dust particles to pass through compared to high-quality paper filters. Warranty implications require verification. Not recommended for extremely dusty environments.
  • Avoid: Extremely cheap, no-name brands found online or in discount bins. These often use inferior materials, causing reduced filtration efficiency, premature clogging, poor fitment risking leaks, or even disintegrating and allowing debris into your engine or HVAC system.

Cost Comparison: DIY vs. Dealership

• Parts Cost:
  • Cabin Filter: Genuine Honda: $25-$40. Quality Aftermarket: $10-$20.
  • Engine Filter: Genuine Honda: $30-$45. Quality Aftermarket: $12-$25. K&N Washable: $50-$60 (plus cleaning kit $15-$20).
• Labor Cost (Dealership Only): Dealerships typically charge 0.3 to 0.5 hours of labor for each filter replacement service. At dealership rates of $150-$200/hour, this translates to $45-$100 in labor charges just to replace these two filters.
• DIY Savings: You can replace both filters yourself with quality parts in 20-30 minutes for less than $50total(partsonly)\ast \ast ,savingpotentially\ast \ast$50-$150 compared to dealership pricing for the same work.

Symptoms Indicating Your Filters Need Replacement

• Cabin Air Filter Failure Signs:
  • Significantly reduced airflow from the dashboard vents, even on high fan speeds.
  • Musty, sour, or unpleasant odors emanating from the vents when the HVAC system is running (A/C or heat).
  • Increased fogging of interior windows.
  • More frequent sneezing or allergy symptoms while driving.
  • Visible dust particles blowing out of the vents.
  • Loud whistling or hissing noise from behind the glove box (severe restriction).
• Engine Air Filter Failure Signs:
  • Noticeably reduced acceleration (engine feels sluggish).
  • Decreased fuel economy (fewer miles per tank).
  • Rough engine idle.
  • Unusual engine noises (dull wheezing sound from the intake area).
  • Illuminated Check Engine Light (CEL). While a clogged filter isn't the direct cause for a CEL, it can contribute to lean fuel mixture codes (e.g., P0171) by disrupting airflow measurements over time.
  • Visibly black and clogged filter element.

Benefits of Regular Filter Changes

• Engine Protection: Prevents abrasive dirt and particles from entering combustion chambers, minimizing wear on pistons, rings, and cylinder walls. Prolongs engine life.
• Enhanced Engine Performance: Ensures the engine gets the precise volume of clean air required for efficient combustion. A clogged filter literally chokes the engine, making it work harder. Maintains optimal horsepower and torque.
• Improved Fuel Economy: Clean air allows the engine control unit (ECU) to maintain the ideal air-fuel mixture. A restricted filter forces the engine to work harder and consume more fuel.
• Optimal Cabin Air Quality: Traps allergens, pollen, dust, pollution, and even some exhaust fumes, creating a healthier breathing environment inside the car, especially beneficial for allergy sufferers and children.
• HVAC System Efficiency & Longevity: A clean cabin filter allows unrestricted airflow, maximizing heating and cooling performance. Reduced strain on the blower motor fan prevents early failure. Prevents musty smells and buildup of debris inside the HVAC ducts and evaporator core.
• Prevention of Costly Repairs: Avoiding damage from contaminants entering the engine or HVAC system prevents expensive repairs like throttle body cleaning, mass airflow sensor replacement, or evaporator core cleaning.

Important Considerations & Tips for 2021 Accord Owners

• VIN-Specific Parts: While most 2021 Accords share the same filters (1.5T and 2.0T engines), always double-check compatibility using your vehicle's VIN when ordering online, especially for specific trims or if uncertain. Dealer parts counters can easily look this up.
• Hybrid Models: The 2021 Accord Hybrid uses the same air filters as its gasoline counterparts. Procedures are identical. Always ensure the vehicle is safely turned off before starting.
• Torque Settings: Filter box clamps and cabin cover screws need to be "snug-tight." Overtightening plastic screws or metal clamps risks cracking or stripping components. Use hand tools only; never power tools.
• Visual Inspection is Key: If in doubt, inspect the filters. Holding them up to a bright light source clearly shows blockage levels. When in doubt, change them early – it's inexpensive insurance.
• Buy Reliable Parts: Stick with Genuine Honda, known major brands (Fram, Bosch, WIX, Purolator, Mann-Filter), or reputable auto parts stores (AutoZone, O'Reilly, Advance Auto Parts, NAPA). Be wary of bargain filters online with questionable reviews.
• Keep Records: Note the date, mileage, and brand/part number of the filters you install. This helps track your maintenance schedule and can be valuable if selling the car.
• Dispose of Old Filters Responsibly: Discard the old paper filters with regular household waste. If using a washable K&N filter, follow their specific cleaning and re-oiling procedures meticulously to avoid damaging your MAF sensor.

Replacing the cabin and engine air filters in your 2021 Honda Accord is among the most straightforward preventive maintenance tasks. Performing this task every 12-15 months or 15,000-30,000 miles (based on driving conditions and filter type) provides substantial benefits for engine health, fuel efficiency, cabin comfort, and HVAC performance. The minimal time and money invested in this DIY job yield significant rewards, protecting your investment and ensuring your Accord continues to deliver a smooth, efficient, and enjoyable driving experience for many miles to come. Start checking your filters today!