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Denso 234-4785 - Oxygen Sensor
Product Overview
The Denso Oxygen Sensor 234-4785 is a premium-quality replacement part designed to monitor the exhaust concentration of oxygen in your BMW vehicle. Engineered to OEM standards, this sensor plays a crucial role in optimizing the air-fuel mixture for gas engines, ensuring efficient operation and reduced emissions. With a typical lifespan of up to 100,000 miles, replacing a failing sensor is essential to prevent further engine issues. Choose Denso 234-4785 for dependable performance and peace of mind every time you service your vehicle.
Cross Reference Numbers
This Denso 234-4785 is equivalent to or replaces the following part numbers: 11781433071, 13761, ES10918, 25045, 250-24516, 350-34180.
Vehicle Compatibility
- BMW 323i 2.5 L6 (1998–1999)
- BMW 323is 2.5 L6 (1998–1999)
- BMW Z3 2.8 L6 (1997–1998)
This may also fit 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 Denso 234-4785 Oxygen Sensor do?
The Denso Oxygen Sensor measures the concentration of oxygen in the exhaust gases of your vehicle. This information is vital for your engine management system to adjust the air-fuel mixture for optimal combustion, contributing to better fuel efficiency and lower emissions.
How do I know if my Oxygen Sensor needs replacement?
Signs that the oxygen sensor may need replacement include poor fuel economy, increased exhaust emissions, engine misfires, and the illumination of the check engine light. If you notice any of these symptoms, it may be time to check the oxygen sensor.
Can I install the Denso 234-4785 myself?
Yes, the Denso 234-4785 Oxygen Sensor can be a DIY installation if you have the necessary tools and experience. However, it is important to follow proper safety precautions and consult your vehicle's service manual for specific instructions.
What are the symptoms of a faulty Oxygen Sensor?
Common symptoms of a faulty oxygen sensor include decreased fuel efficiency, rough engine performance, increased exhaust emissions, and the check engine light illuminating. If you see DTCs such as P0130, P0131, P0132, P0133, P0134, and P0135, it may indicate a failing oxygen sensor.
Why should I choose Denso for my Oxygen Sensor needs?
Denso is a trusted brand known for its commitment to quality and performance. Order Denso 234-4785 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.
- BrandDenso
- ManufacturerDenso
- MPN234-4785
- Part TypeOxygen Sensor
- OE Part Numbers11781433071
- Cross Reference Numbers2344785, 250-24516, 25024516, ES10918, 25045, 350-34180, 35034180, 13761
- FeaturesConnector Gender : Female
Mounting Type : Threaded
Sensor Type : Heated
Thread Diameter : 0.708
Universal Or Specific Fit : Specific
Wire Quantity : 4
Wiring Harness Length : 15.75
- Fitment
- Fitment TypeVehicle Specific
| Year | Make | Model | Submodel | Notes |
|---|---|---|---|---|
| 1999 | BMW | 323i | Base (2.5 L6 GAS) | Position: Downstream, Notes: w/ 16" Downstream Sensor, O.E. Quality Direct Fit Replacement Sensor |
| 1999 | BMW | 323is | Base (2.5 L6 GAS) | Position: Downstream, Notes: w/ 16" Downstream Sensor, O.E. Quality Direct Fit Replacement Sensor |
| 1998 | BMW | 323i | Base (2.5 L6 GAS) | Position: Downstream, Notes: w/ 16" Downstream Sensor, O.E. Quality Direct Fit Replacement Sensor |
| 1998 | BMW | 323is | Base (2.5 L6 GAS) | Position: Downstream, Notes: w/ 16" Downstream Sensor, O.E. Quality Direct Fit Replacement Sensor |
| 1998 | BMW | Z3 | Roadster (2.8 L6 GAS) | Position: Upstream, Notes: To 09/1998, O.E. Quality Direct Fit Replacement Sensor |
| 1997 | BMW | Z3 | Roadster (2.8 L6 GAS) | Position: Upstream, Notes: To 09/1998, O.E. Quality Direct Fit Replacement Sensor |
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.






