Altering the factory catalysts will often lead to a check engine light as the emissions systems are no longer running as designed. Modern cars rely on two O2 sensors per bank, the primary sensor is before the catalytic converter and monitors the chemical makeup of the exhaust gases before they have been catalyzed. The secondary O2 sensor is after the catalytic converter. It measures the makeup of the exhaust gases after they have been catalyzed and reports the information back to the ECU. The ECU will then compare the readings to determine if the catalytic converter is working properly. The O2 spacer moves the O2 sensor out of the direct stream of gases which will help restore the balance expected from the ECU. We have used these on many cars to eliminate check engine lights after the installation of catless headers.
+ Fitment is UNIVERSAL – please check for available space for installation prior to purchasing
+ For use ONLY in the Secondary (post cat, downstream) O2 sensor
+ Emissions compliance not guaranteed