my VW Passatv62.8LS/W has aP2096 code, shud we replace all 4 o2 sensors to solve

why would you do that?check for vacuum leaks all over the engine area.that code does not mean for you to start throwing parts at it.some of the vacuum hoses may be covered and hard to find a leak,but inspect all of them,listen for hissing sounds,with engine running.Since the code indicates a post cat lean condition on both banks of the engine, the total mixture is the likely culprit. A lot of these end up being the fuel filter(I recommend every 15k miles), the MAF needing cleaned, the snow screen being clogged in the air filter assy inlet. Since you have code for one bank of the motor, the exhaust and O2 sensor aren't likely culprits unless one flexible union is cracked(braided stainless section). The fuel trims before the cats is OK or the computer would have flagged lean codes P0171, etc. The freeze frame data of when the code set would be super helpful, if you have access to a scanner. you could see when the code set and what exactly was happening at that time. Possible causes - Low fuel pressure - Misfire condition - Large vacuum leak - Air leak near sensor - Plugged catalytic converter - Lean air/fuel ratio - Faulty front O2 sensor