2017-2023 Subaru Impreza Rear Bumper Cover: Sedan vs. Hatchback & Sensor Guide
This guide details the critical differences between Sedan and Hatchback rear bumpers and how to identify versions with and without parking sensors to ensure you buy the right part.
- The single most important factor is body style: Sedan (4-door) and Hatchback (5-door) bumpers are NOT interchangeable.
- You must get a bumper that matches your car's sensor configuration (with or without holes for Park Assist/RAB).
- When buying used, the condition of the plastic mounting tabs is more important than cosmetic scuffs. Broken tabs mean the bumper will not fit correctly.
- A warning light for 'RAB Off' can be caused by a dirty sensor or minor bumper damage that misaligns a sensor.
Critical Bumper Variations: Sedan vs. Hatchback and Sensor Options
Before purchasing a rear bumper cover for a 2017-2023 Subaru Impreza, you must correctly identify your vehicle's body style and sensor configuration. Ordering the wrong part is the most common and costly mistake. The covers are not interchangeable between body styles or sensor setups.
Warning: A bumper cover for a Sedan will not physically fit on a Hatchback (also called a 5-door or Wagon), and vice-versa. Always confirm your body style before ordering.
Identifying Your Bumper Type:
There are four main versions of the rear bumper cover for this generation of Impreza. The key differences are the body style and the presence of circular cutouts for parking sensors.
| Vehicle Body Style | Sensor Configuration | Common OEM Part Number(s) | Common Partslink Number(s) |
|---|---|---|---|
| Sedan (4-Door) | Without Parking Sensors | 57704FL21A | SU1100183 |
| Sedan (4-Door) | With Parking Sensors | 57702FL21A | SU1100184 |
| Hatchback / Wagon (5-Door) | Without Parking Sensors | 57704FL20A | SU1100185 |
| Hatchback / Wagon (5-Door) | With Parking Sensors (for Park Assist / RAB) | 57702FL20A | SU1100186 |
Parking sensors are used for two related features: simple Park Assist (beeping) and Reverse Automatic Braking (RAB), which can actively apply the brakes. If your car has either feature, you need a bumper with sensor holes.
Symptoms of a Damaged Rear Bumper Cover
While some symptoms are obvious, others can be electronic and appear unrelated to the bumper itself.
- Visible Damage: This includes cracks, deep gouges, punctures, or paint that is severely scraped or peeling. Minor scuffs may be cosmetic, but cracks compromise the part's integrity.
- Poor Fitment: Look for uneven gaps between the bumper cover and the tail lights or quarter panels. The cover may appear loose, saggy, or have clips that have popped out of place.
- 'RAB Off' or Park Assist Warning Lights: If the bumper is hit, even lightly, it can knock a sensor out of its mounting bracket or damage its wiring. This will cause the vehicle's computer to disable the Reverse Automatic Braking or Park Assist systems, often displaying a warning message on the dashboard. Even a layer of dirt or snow can sometimes cause these warnings.
Buying a Used 2017-2023 Impreza Rear Bumper Cover
A used OEM (Original Equipment Manufacturer) bumper cover is often a better choice than a new aftermarket part, as it guarantees perfect fitment and material quality. However, you must inspect it carefully.
Inspection Checklist:
- Confirm the Part Number: First, ensure it's the correct part for your Sedan or Hatchback and sensor configuration using the table above.
- Check All Mounting Tabs: This is the most critical inspection point. Carefully examine the top, side, and bottom edges for small plastic tabs. If any of these are cracked, broken, or stressed (showing white bend marks), the bumper will not sit flush against the body. Do not buy a cover with broken tabs.
- Look for Prior Repairs: Check the backside of the cover. Look for signs of plastic welding, excess glue, or body filler (often called 'Bondo'). A previously repaired bumper may not hold up in another impact and can have paint adhesion issues.
- Inspect for Warping: Lay the bumper on a flat floor to check for any twisting or warping. A distorted bumper, often from sitting in the sun after a minor impact, will never align correctly.
- Verify Sensor Holes: If you need a bumper with sensors, ensure the holes are perfectly round and factory-molded. Damaged or crudely drilled holes will not hold the sensors securely, leading to RAB and Park Assist errors.
Pro Tip: Finding a used bumper cover in the exact same color as your car can save you hundreds of dollars in paint costs. Use online recycled parts locators like car-part.com to search salvage yards nationwide by paint code.
Known Issues, TSBs, and Recalls
As of mid-2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) for the rear bumper cover on the 2017-2023 Subaru Impreza. However, owners frequently report issues with the Reverse Automatic Braking (RAB) system being overly sensitive. The system may brake abruptly when backing up near tall grass, a steep driveway incline, or when towing a trailer. This is a characteristic of the system's design rather than a fault, but can be surprising if you are not expecting it.
Replacement Overview & Difficulty
- Difficulty Rating: 2 out of 5 (without sensors); 3 out of 5 (with sensors)
- Estimated Time: 1.5 - 2.5 hours
- Tools Required: Phillips screwdriver, flathead screwdriver, 10mm socket/wrench, plastic trim removal tools.
Replacing the rear bumper cover is a manageable DIY project. The general steps involve:
- Opening the trunk and removing plastic clips holding the trunk trim and floor.
- Removing the tail light assemblies (typically held by two 10mm bolts each) to access bumper clips underneath.
- Removing screws and plastic clips from inside each rear wheel well.
- Removing clips along the bottom edge of the bumper cover.
- If equipped, carefully disconnecting the wiring harness for the parking sensors.
- Gently pulling the sides of the bumper cover away from the vehicle to release it from the retaining brackets under the tail lights.
Pro Tip: When transferring parking sensors to a new bumper, be extremely gentle. The plastic clips that hold them in place are fragile. Ensure each sensor 'clicks' securely into its new mount to prevent alignment-related errors.
Cost Comparison (2017-2023 Impreza Rear Bumper Cover)
Prices can vary based on supplier and location. These are typical estimates.
| Part Type | Estimated Cost | Notes |
|---|---|---|
| New OEM (Unpainted) | $200 - $350 | Genuine Subaru part that requires painting. |
| New Aftermarket (Unpainted) | $150 - $250 | Quality and fit can vary. CAPA-certified parts are recommended for better fitment. |
| Used OEM (Color-Matched) | $250 - $500+ | Price depends heavily on condition and color availability. Can be a great value if no painting is needed. |
| Shop Labor (Installation) | $150 - $250 | Cost for a body shop to remove the old bumper and install a new one. |
| Shop Labor (Painting) | $400 - $600 | Cost to prep, paint, and clear-coat an unpainted bumper to match your vehicle's color. |
Frequently Asked Questions
Do I have to get the new bumper cover painted?
Yes. All new OEM and aftermarket bumper covers are shipped in a black or grey primer finish. They must be professionally painted and clear-coated to match your vehicle and protect the plastic from UV damage.
Can I install a bumper with sensor holes on my car that doesn't have sensors?
While it might physically fit if the body style is correct, you would be left with four open holes in your bumper. Aftermarket plugs are available, but they are often visually obvious and may not provide a perfect seal.
My 'RAB OFF' light is on after a minor bump. Do I need a new bumper?
Not necessarily. First, thoroughly clean the sensors to ensure dirt isn't the cause. If the light remains, the impact may have simply dislodged a sensor from its mounting clip or disconnected its wiring. A technician may be able to remount the sensor without replacing the entire bumper cover, provided the cover itself isn't cracked or distorted where the sensor mounts.
Why do forum users recommend a used OEM bumper over a new aftermarket one?
Fitment and durability. A genuine Subaru bumper is guaranteed to align with all body panels and mounting points perfectly. Some cheaper aftermarket bumpers can have slight shape differences, leading to uneven gaps or difficulty during installation. The plastic used in OEM parts is also often more flexible and durable.
Technical Specifications
OEM Part Numbers: 57704FL21A (Sedan, w/o sensors) 57702FL21A (Sedan, w/ sensors) 57704FL20A (Hatchback, w/o sensors) 57702FL20A (Hatchback, w/ sensors)
Material: Polypropylene Plastic. Finish: Primed/Unpainted.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Subaru Impreza:
- Critical Bumper Variations: Sedan vs. Hatchback and Sensor Options
- Identifying Your Bumper Type:
- Symptoms of a Damaged Rear Bumper Cover
- Buying a Used 2017-2023 Impreza Rear Bumper Cover
- Inspection Checklist:
- Known Issues, TSBs, and Recalls
- Replacement Overview & Difficulty
- Cost Comparison (2017-2023 Impreza Rear Bumper Cover)
- Frequently Asked Questions
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