HELP P1168 and P0141 CODES
 

I have a 2003 4.4i E53. I got a SES light come on, took it to get OBDII scan reader to get code and it says P1168 (Fuel Air or Fuel Rail Sensor) and P0141 (02 Sensor heater circuit malfunction Bank 1 Sensor 2). Does anyone know if I should just replace all four sensors and this should solve the problem, i have 78K miles. Or is it something else that is triggering the SES light? Any one have these codes and what was the fix?
Thanks in advance!

How much does it cost to replace the 02 sensors?

The Pre Cat is 80 each and Post Cat is 90 each, there are 2 pre and 2 post, so almost 400 bucks including tax! I checked below and there are a lot of clips holding them up as they route and the passenger side it looks hidden and hard to get to.

Changing O2 sensors won't solve anything. I would check for air leaks, cracked air boot or vaccum lines, maybe a torn OS hose.

FYI:

Help with OBD Code P1168 - Bimmerforums - The Ultimate BMW Forum

Penguin, read that article actually in my search. But I don't want to spend the money if that isn't the fix, SFCL gave me some good hints to look for, and I did some more digging and found someone who had a similar issue, and he found it to be 2 cracks in the rubber air boot i think between air flow meter and throttle body? Now I just need to figure out where this is located and also how do you check for vacuum leaks in vacuum lines???

Intake air boot: #4 on this diagram: RealOEM.com BMW E53 X5 4.4i Hot-film air mass meter

Vaccum lines: You have the choice! There are many, at least 2 of them come to the intake boot

Maybe you should check also the state of the OS hoses: RealOEM.com BMW E53 X5 4.4i Crankcase-Ventilation/oil separator

Well, visual inspection is the first way.

The second way is to spray something near the leak that will get sucked into the leak and change the engine RPM or sound. Some people have used an UNLIT propane torch for this; however, I typically use carb cleaner or some WD-40 spray. WD-40 spray is less likely to mar or damage any plastic parts.

You spray the WD-40 where you suspect there may be a vacuum leak, and if there is one there, it will suck some WD-40 in and the engine RPM will change.

Do a Google on "automotive vacuum leak diagnosis" and you'll get a lot of links.

Thanks! I opened the hood and did a visual but didn't notice anything obvious with naked eye, now with diagram in hand I can take a closer look at these items!

Thanks, yeah a guy at work told me to be careful with carb spray it can ignite? SO I will stick to WD-40 which i have readily available already. Another guy told me at work that the Fuel Rail Sensor code could be a sign of fuel pump failure or something of that nature...