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          Bosch 13721 - Oxygen Sensor (Upstream)

          MPN: 13721
          The Bosch 13721 Oxygen Sensor ensures your Porsche maintains optimal engine performance by accurately measuring exhaust oxygen levels. Designed for specific models for reliable fitment.
          0.0
          Vehicle Specific
          Check if this part fits your vehicle.
          • $89.95
          In stock

          Product Overview

          The Bosch Oxygen Sensor 13721 is an essential component for maintaining the optimal performance of your Porsche. Designed to monitor the exhaust concentration of oxygen, this premium-grade sensor plays a crucial role in ensuring your engine runs efficiently while minimizing emissions. Engineered to meet or exceed OEM standards, this oxygen sensor is trusted by both DIY enthusiasts and professionals alike. Choose Bosch 13721 for dependable performance and peace of mind every time you service your vehicle.

          Cross Reference Numbers

          This Bosch 13721 is equivalent to or replaces the following part numbers: 993 606 116 01, 99360611601.

          Vehicle Compatibility

          • Porsche 911 Carrera 3.6 H6 (1995–1998)
          • Porsche 911 Carrera 4 3.6 H6 (1995–1998)
          • Porsche 911 Carrera 4S 3.6 H6 (1997–1998)
          • Porsche 911 Targa 3.6 H6 (1996–1998)
          • Porsche 911 Carrera S 3.6 H6 (1998)

          This may also fits other applications. Please use the vehicle selector tool to verify fitment.

          Why Shop at eEuroparts.com?

          • Proven Expertise: Over 25 years of experience with European vehicles means we know your car inside and out.
          • Exclusive Kits That Fit™ - complete repair solutions with no guesswork
          • Fitment Confidence: Our accurate cataloging ensures you get the right part the first time.
          • Fast, Reliable Shipping: Orders ship quickly from our U.S.-based warehouses.
          • Transparent Pricing: Competitive prices with no hidden fees or surprise charges.
          • Established Trust: Serving the European auto community since 2000.

          Frequently Asked Questions

          What does the Bosch 13721 Oxygen Sensor do?

          The Bosch Oxygen Sensor measures the concentration of oxygen in the exhaust gases of your vehicle. This data helps the engine control unit adjust the air-to-fuel mixture for optimal combustion, improving fuel efficiency and reducing emissions.

          How do I know if my Oxygen Sensor needs replacement?

          Key signs that your oxygen sensor may need replacement include poor fuel economy, rough engine idle, illuminated check engine light, and increased emissions. If you notice any of these symptoms, it may be time to replace your oxygen sensor.

          Can I install the Bosch 13721 myself?

          Yes, the Bosch 13721 can be installed as a DIY project. However, ensure that you follow proper safety precautions and refer to your vehicle's service manual for detailed installation instructions.

          What are the symptoms of a faulty Oxygen Sensor?

          Common symptoms of a faulty oxygen sensor include poor acceleration, decreased fuel efficiency, and an illuminated check engine light. If you see DTCs such as P0130, P0131, P0132, P0133, or P0134, it may indicate a failing oxygen sensor.

          Why should I choose Bosch for my Oxygen Sensor needs?

          Bosch is a trusted brand known for its high-quality automotive components. Order Bosch 13721 today for a factory-correct replacement that restores safety and performance.

          Note: All information on this page and in the FAQ is for general reference only. Verify fitment and consult a professional as needed. eEuroparts.com is not responsible for incorrect part selection or installation.

            • eEuroparts SKU
              235679
            • Weight
              0.3836 lbs
            • Dimensions (L x W x H)
              2.2047 x 1.9685 x 5.8268 in
            • Barcode
              00028851137218
            • Manufacturer Part #
              13721
          • Brand
            Bosch
          • Manufacturer
            Bosch
          • MPN
            13721
          • Part Type
            Oxygen Sensor
          • Position
            Upstream
          • OE Part Numbers
            99360611601
          • Features
            Automotive Color / Finish : Steel
            Automotive Item Weight (lbs) : 0.343921 lb
            Connector Gender : Male
            Connector Shape : Oblong
            Grade Type : Regular
            Heated (Oxygen Sensor) : Yes
            Hex Size (Oxygen Sensor) : 22 mm
            Housing Material : Metal
            Length (Sealing Surface To End Of Connector) : 33.0708661417323 in
            Mounting Bracket Included : No
            Mounting Type : Threaded
            Overall Length : 34.251968503937
            Oxygen Sensor Type : Narrow-band heated
            Prop 65 Warning Label Required? : No
            Sensor Type : Heated
            Terminal Gender : Male
            Terminal Quantity : 4
            Terminal Type : Blade
            Thread Diameter : 18
            Thread Size : 18
            Universal Or Specific Fit : Specific
            Wire Quantity : 4
            Wiring Harness Included : Yes
            Wiring Harness Length : 30.5511811023622
          • Fitment
            • Fitment Type
              Vehicle Specific
          YearMakeModelSubmodelNotes
          1998Porsche911Carrera (3.6 H6 GAS)
          1998Porsche911Carrera 4 (3.6 H6 GAS)
          1998Porsche911Carrera 4S (3.6 H6 GAS)
          1998Porsche911Carrera S (3.6 H6 GAS)
          1998Porsche911Targa (3.6 H6 GAS)
          1997Porsche911Carrera (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1997Porsche911Carrera 4 (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1997Porsche911Carrera 4S (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1997Porsche911Targa (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1997Porsche911Turbo (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1996Porsche911Carrera (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1996Porsche911Carrera 4 (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1996Porsche911Carrera 4S (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1996Porsche911Targa (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1996Porsche911Turbo (3.6 H6 GAS)Aspiration: Naturally Aspirated
          1995Porsche911Carrera (3.6 H6 GAS)
          1995Porsche911Carrera 4 (3.6 H6 GAS)
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          Warranty Overview

          At eEuroparts, we stand behind the quality of the products we sell. Every part we offer is backed by a warranty designed to give you peace of mind and protect your investment.

          Standard Warranty – Most Parts

          • Coverage: 2 years or 24,000 miles (whichever comes first) from purchase date.

          • Protection: Defects in materials or workmanship under normal personal use.

          • Eligibility: Applies only to the original purchaser and the vehicle where the part was first installed.

          • Exclusions:

            • Wear-and-tear items (brake pads, filters, bulbs, wipers, etc.)

            • Commercial, fleet, rideshare, off-road, or racing use

            • Improper installation, misuse, accidents, or modifications

          • Not Covered: Labor, shipping, towing, or incidental costs.

          Bison Performance Warranty – Our House Brand

          • Coverage: Limited Lifetime Warranty for as long as you own your vehicle.

          • Applies To: All products sold under the Bison Performance label.

          • Premium Protection: Goes beyond our standard warranty — if it’s a Bison product, the 2-year/24k mile limit is replaced with lifetime coverage.

          • Exclusions: Same as the standard warranty (normal wear, commercial use, improper installation, etc.).

          • What’s Included: Replacement of the defective product (labor and shipping excluded).

          Warranty Claim Requirements

          To keep claims fast and fair, we require:

          • Proof of purchase (invoice or order confirmation).

          • Photos or videos showing the defective part, order number, date, VIN, and odometer reading.

          • Diagnostic reports or part returns for non-visible issues may be requested.

          • Claims must be truthful, properly documented, and reflect normal consumer use.

          Buy With Confidence: We back our products because we believe in their quality, with a transparent, customer-first warranty process you can trust. And with Bison Performance products, you’ll enjoy Limited Lifetime protection—an assurance few brands can match.

          For full details and exclusions, please see our complete Warranty Terms & Conditions.

          This summary is for convenience only. For full warranty coverage details, exclusions, and requirements, see our official Warranty Terms & Conditions. In case of conflict, the full policy governs.

          Return Policy Overview

          Most parts can be returned within 30 days of delivery if unused, uninstalled, and in original packaging.
          To start a return, contact customer support via Chat or Contact Us.

          • Restocking fee: Up to 20% may apply for certain orders (buyer’s remorse, order errors, or special-order items)

          • Refunds: Issued to your original payment method within 3–5 business days after inspection

          • Exchanges: Not automatic — please return and reorder

          • Replacements: May be approved for incorrect or defective items reported within 7 days

          Not returnable:

          • Used or installed parts

          • Electrical components

          • Opened filter kits, gaskets, or contaminated items

          • Final sale or custom orders

          Important Notes:

          • Return shipping is your responsibility unless we made a verified error

          • Fitment is the customer’s responsibility (we can assist, but do not guarantee)

          • Country of origin may vary and is not grounds for return

          For complete details, please see our full Return Policy.


          This Returns summary is provided for convenience only. All returns, refunds, and exchanges are subject to the complete Returns Policy. In the event of any conflict, the full policy governs.

          Fast, Reliable Shipping — Straight to Your Door

          We ship most orders the same day when placed before 2 PM CST (Monday–Friday). Our main warehouse is just east of Nashville, TN, and we also ship from multiple locations nationwide to get your order to you as quickly as possible.

          • We use trusted carriers like UPS, FedEx, and USPS.

          • Tracking info is emailed to you as soon as your order ships.

          • Delivery estimates at checkout are based on carrier data, but not guaranteed.

          Need help with a shipment?

          If your order is missing, damaged, or incorrect, just let us know within 5 days of delivery. We’ll walk you through the quick claim process — including a few photos to help us make things right.

          For complete details, please see our full Shipping Policy.


          This Shipping summary is provided for convenience only. Delivery times, carrier terms, fees, restrictions, risk of loss, and other details are governed by our complete Shipping Policy. In the event of any conflict, the full policy governs.

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