AEM ’s legendary Digital Wideband O2 AFR UEGO Gauge is a wideband UEGO air/fuel ratio controller (AFR) and gauge in one. It unites accuracy, speed and control with an easy to read, digital LED display and sweeping LED “needle ” that changes colors as AFR changes from rich to lean.

NOTE: The 30-4100 Wideband UEGO Gauge Controller that uses the Bosch 4.2 LSU sensor will be superseded to the 30-4110 Wideband UEGO Gauge Controller that uses the Bosch 4.9 LSU sensor in August 2014. Instructions for the 30-4100 will still be available in the Instructions tab after this change.