if it works, take it
apart to finde out
AO Silver Member
Join Date: Dec 2008
Your pre cat lambda sensor switching between 0,1 and 0,9V seems OK and your post cat lambda sensor should be pretty stable around 0.5-0,7V (a bit on the rich side as the cat burns oxygen) but you won't see the ECU switching to close loop and make use of the lambda sensor integrator for the post cat lambda until you rev. the engine a bit (the ECU don't use post cat lambda sensor at idle speed).
Your voltage reading for post cat lambda may indicate a small air leak on the exhaust around the cat/post lambda.