Key Features
Fastest Wideband AEM Has Ever Built
X-Series technology gives:
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Lightning-quick AFR updates
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Ultra-stable readings
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Exceptional accuracy under boost
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Cleaner data for ECUs & loggers
AEM’s X-Series wideband UEGO Air/Fuel ratio sensor controller gauges are built upon unique, patent-pending X-Digital technology that makes them the fastest responding wideband air/fuel ratio controllers in independent testing against 17 other wideband UEGO air/fuel controllers.
Bosch LSU 4.9 Sensor Included
Industry favorite for:
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Long life
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Fast heat-up
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Consistent Lambda accuracy
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Reliable performance in extreme heat
From the manufacturer
52mm (2-1/16”) Digital Display
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Large central AFR readout
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Bright outer LED ring
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Slim profile for tight gauge pods
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Interchangeable black/white faces & bezels
Advanced Output Options
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0–5V analog output for standalone ECUs
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Serial output for dash displays and loggers
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Ideal for tuning, dyno sessions, and safety control circuits
Built-In UEGO Controller
No external box required—clean install, minimal wiring.
Why Tuners and Builders Choose the 30-0300
Accurate AFR is the backbone of:
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Turbo tuning
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E85 calibration
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High-boost safety
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Standalone ECU mapping
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Carbureted fuel mix adjustment
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Knock prevention
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Turbo spool optimization
This gauge reacts faster—and reads more accurately—than virtually any other consumer wideband on the market.
X-digital technology:
X-Digital wideband technology gives these controllers the ability to read and report values that other controllers do not, which can deliver more optimized engine tuning and a safer overall operating condition. The controller’s high-speed digital implementation ensures no loss of signal fidelity and full transient response, making it able to identify the slightest fluctuations in AFR and output them in full value.
Installation Notes
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Install wideband bung at least 18 inches from turbo (if boosted)
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Never mount sensor at the very bottom of the pipe (condensation kills sensors)
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Route wiring away from downpipes and manifolds
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Use analog output for ECU-based fuel/timing safeties
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Use serial output for digital dashboards or logs
Install time: 30–60 minutes.
Factory calibration resistor or free-air cal, it’s your choice!: The X-Series Wideband Gauge and X-Series Inline Controller support the popular Bosch 4.9LSU sensor and can utilize both the factory calibration resistor and free-air calibration methods**. This allows users to take advantage of the precise factory resistor calibration when a sensor is new but then allows for free-air calibrations if the user desires when the sensor ages. It’s the perfect marriage of simplicity and accuracy!
Features:
- X-Series Wideband UEGO AFR Controller Gauge were fastest responding wideband air/fuel ratio controllers in an independent test vs. 17 competitors wideband AFR controllers
- Includes Bosch 4.9LSU wideband UEGO sensor
- Factory calibrated resistor does not require free-air calibration, but technology allows for free-air calibration as sensor ages if user desires
- Compatible with vehicle/system voltages up to 16V
- 0-5V & RS232 output for data logging and feedback control, AEMnet (CANbus) for data logging and daisy-chaining multiple controllers up to 16 cylinders
- Can display AFR values in hundredths of %
- 52mm gauge diameter and slim 0.825” gauge depth
- Gauge cup depth only .200” deep!
- Auto dimming feature
- User configurable display via buttons on the gauge face for changing AFR values, Lambda and O2%, and 3- or 4-digit display
Final Verdict
The AEM 30-0300 X-Series Wideband UEGO AFR Gauge is the top choice for serious tuners and performance enthusiasts.
With unmatched response speed, rock-solid accuracy, and full ECU/datalogger compatibility, it’s the wideband you buy when you want your engine to live—and perform.
If you run boost, ethanol, or a standalone ECU, this is the AFR gauge you should be using. No exceptions.
William B. –
I’m writing this for people on the fence about whether it is the real AEM gauge/sensor or not. It is, I went to AEM’s website and compared the part numbers and pics and it is exactly the same. I installed it per instructions and warnings and it is working perfectly. It’s a good deal and a great product.
aaron –
Easy installation and a great tool getting my motor tuned
Ian –
Works good and reads AFR’s as it should.
Yosuan Noriega –
Easy to wire up and works great.
Brian H. –
Love it since I’ve had it no issues at all. If you got this and are trying to figure out the wiring for a 07-14 chevy and a Pro-Link just add me on FB and message me and I’ll shoot a pic of the wiring. Brian Harvill (verified)
reece –
Product came as described & brand new
T –
As promised, I’m updating this review based on the customer service experience. I installed this to replace a dying old 14point7 gauge and it was DOA. It just read “SEnS” when I powered it up, despite having good wiring continuity. I emailed AEM with a specific description of the issue and they had me call and arrange for a replacement, there was no hassle and the customer service people were friendly. When all was said and done, I put the new one in with the already-installed wiring and it works fine.I like the responsiveness of its output for tuning and the sweeping LED part of the display is useful for visualizing transients like acceleration enrichment when you don’t have your laptop hooked up. The only negative about this unit is that the bezel is thick compared to most other wideband gauges, and based on the form factor of the actual gauge part the size of this part is pretty excessive. It’s also gloss black, which doesn’t match the satin/matte black of most interiors and gauge bezels, but I just had to remove the bezel and paint it to rectify this.Tip: don’t go through all of the hassle of running the wires and stuff until you bench test it out of the box. That way you know it’s functioning before spending a few hours fighting with grommets and taking interior parts out to run wires cleanly.
Hypergames –
Its only letting me do 4 but this product is top of the line. Perfect reading. It doesnt break if you READ THE INSTRUCTIONS. Too many people put it in a way that the water cant escape then they say its garbage. No it aint
Salomon zapata –
Excelente
Tengo 2 meses de uso y está funcionando perfectamente
Guillermo Mendoza –
Rapido y original
Perfexto funcionamiento, calidad superior