I just installed the plx m-200 wideband and now I get a check engine light. Using it as a standalone, red to power, black to ground, grey to ecu NB input. check engine light is a code 41 (o2) obviously. Can anyone point me in the right direction?

 

what do you mean your using the plx as stand alone? do you have the NB o2 sensor in? If you removed your stock o2 then you need a means to disable it. more info would help.

 

You need to disable the o2 heater circuit.