AEM X-Series Wideband UEGO AFR Gauge Kit with Sensor - 30-0300

The AEM 30-0300 is a 52 mm digital gauge with a built-in wideband controller that measures air/fuel ratio (AFR) for monitoring and tuning. The kit includes an AEM/FAE wideband oxygen sensor and a weld-in bung.

Already running a wideband sensor? The X-Series wideband gauge without sensor works only with an AEM/FAE or Bosch LSU 4.9 wideband sensor. Factory narrowband O2 sensors and Bosch LSU 4.2 sensors will not work with it.

Fitment and requirements

• Gas, E85 or race-fuel engines, carbureted or EFI, where you can weld the supplied bung into the exhaust
• AEM places the sensor about 18 inches downstream of the exhaust port or turbo, and ahead of any catalytic converter
• Needs switched 12V power and ground

What it does

• Shows AFR, lambda or O2 percent, switchable from the face buttons
• Auto-detects an AEM/FAE or Bosch LSU 4.9 sensor and shows which one is connected
• Free-air or resistor-trim calibration modes
• Typical response time 20 ms (AEM rating)
• 0-5V analog, RS232 and AEMnet CAN outputs for logging
• Accepts up to 16V supply
• 52 mm (2-1/16 inch) body with a slim 0.825 inch depth

What is in the box

• X-Series AFR gauge
• AEM/FAE wideband oxygen sensor
• Weld-in mild steel O2 sensor bung
• Sensor cable and power/IO cable
• Mounting bracket and knurled nuts
• Butt connectors

Installation and limitations

Weld the bung where AEM recommends, about 18 inches after the exhaust port or turbo and before any catalytic converter. Power the gauge from switched 12V so the sensor heater shuts off with the key.

Running with the sensor installed but unpowered, or on leaded fuel, shortens sensor life. Full details: AEM X-Series wideband instructions (PDF).

Specifications

• Part number: 30-0300
• Brand: AEM
• Warranty: 1 year manufacturer warranty
• Country of origin: United States
• Packaged size: 5.5 x 5.4 x 5.3 in, 1.33 lb
• UPC: 840879024437

Frequently asked questions

Does the AEM 30-0300 kit include an oxygen sensor?

Yes. It includes an AEM/FAE wideband sensor and a weld-in bung. The 30-0300NS is the same gauge without the sensor.

Which replacement sensors work with the 30-0300?

AEM/FAE wideband sensors and Bosch LSU 4.9 sensors; the gauge detects which one is connected. The Bosch LSU 4.9 replacement sensor 30-2004 is a Bosch LSU 4.9.

Can I log the 30-0300 with an HP Tuners MPVI4?

Yes, with extra hardware. Wire the gauge 0-5V output into an analog input through HP Tuners' PROLINK+ cable (sold separately) and enter AEM's output scaling from the instructions in VCM Scanner. See the HP Tuners MPVI4.

Can I change the bezel color?

Yes. The silver bezel and white face kit 30-0300-ACC swaps in a silver bezel and white face.