2014-2021 BMW i3 REx/i3s REx Oxygen Sensor / O2 11788603903
OEM Part #: 11-78-8-603-903 (11788603903)
Actual photo
The exact part you’ll receive — not a stock photo.
$27.99
Used
Donor2015 BMW i3 · 0.6L · 56k miles
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Genuine OEM Used
SKU: 526127
Donor Vehicle: 2015 BMW i3 · 0.6L · 56k miles
2 photos
$27.99
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Genuine OEM Used
SKU: 572383
Donor Vehicle: 2014 BMW i3 · 0.6L
2 photos
$27.99
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Genuine OEM Used
SKU: 504608
Donor Vehicle: 2016 BMW i3 · 0.6L · 40k miles
2 photos
$27.99
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Genuine OEM Used
SKU: 628542
Donor Vehicle: 2014 BMW i3 · 0.6L · 84k miles
2 photos
$31.99
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This BMW oxygen sensor (O2 sensor), OEM part number 8603903, is a genuine used unit removed from a donor vehicle. It’s designed for the range-extender engine — a 0.6L 647cc L2 SOHC — found in the BMW i3 and i3s. Also called an O2 sensor, it monitors exhaust oxygen levels to help the engine control module adjust the fuel mixture. A failing sensor can trigger a check engine light, cause poor fuel economy, or lead to rough idle on the REX unit.
Specifications
| Fits Vehicle Model | i3 REx, i3s REx |
| Fits Vehicle Make | BMW |
| OEM Part No | 11-78-8-603-903 (11788603903) |
| Category | Exhaust |
Compatible Vehicles
Fits 12 vehicle configurations across 1 make, 2014-2021.
Check your specific vehicle before ordering.
This list shows year, make, and model. Some years have multiple trims or
engines that use different parts, and individual listings may have
additional fitment notes (e.g. “with sunroof only”). Review
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and we’ll confirm the match.
View all 12 vehicle configurations
| Year | Make | Model | Trim | Engine | Note |
|---|---|---|---|---|---|
| 2014 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2016 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2015 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2017 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2018 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2019 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2020 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2021 | BMW | i3 REx | Hatchback | 0.6L l2 | |
| 2019 | BMW | i3s REx | Hatchback | 0.6L l2 | |
| 2018 | BMW | i3s REx | Hatchback | 0.6L l2 | |
| 2020 | BMW | i3s REx | Hatchback | 0.6L l2 | |
| 2021 | BMW | i3s REx | Hatchback | 0.6L l2 |