535Paul

Hi everyone,

I have a 2008 535i that is stock for the most part besides DCI, muffler delete, and MHD flash (currently on stock map). I had the JB4 previously but ran into some issues with CEL so it was removed and MHD added for monitoring and flashing. I am running into some issues with a 30FF and also O2 issues which all started getting worse after running 50/50 E85 for about 2-3 months, I got CEL for 3 out of 4 O2 and had all 4 of them replaced. I am running 91 now and starts and runs fine, (sometime it will idle rough for a few seconds after cold start) and has plenty of power off the line. I will get a reduced power warning about 4-5k RPM if I am WOT. Here are the codes I get after clearing everything and driving around the block mostly WOT.

2C3E Oxygen Sensor 2 before cat - line fault
2CA7 O2 Sensor Heater cat - function
2CAB O2 Sensor before cat - tempature
2E8E Intelligent battery sensor missing
2FA3 No Coding
30FF Turbocharger pressure too low

Recent repairs:
Walnut Blasting, Ignition Coils, Plugs, 4x O2 Sensors

y0itzflip

i get 30ff as well but i dont have all those errors. id clear the codes and see what comes back as start.

535Paul

These codes are after driving the car for about 5 minutes. Are you saying reset and don't drive it at all, just idle until codes come?

seanjordan20

It looks like you have either a vacuum leak, leaking injector or faulty sensors. Were these OE sensors or OEM. More than likely there is leak some where and your sensors were never bad to begin with.

NoQuarter

I am in complete agreement here. Your first priority is to figure out why boost is too low and vacuum is nbr one thing to check out.

535Paul

The replacement sensors are all Bosch, I saw a post about doing a pressure test to check for leaks and can do that this weekend. How would I test for a leaking injector? Wouldn't that cause a misfire if it was just one injector?

seanjordan20

Not necessarily. A failed injector would cause one a leaking injector would cause fuel not to be ignited causing an O2 fault. Check for vacuum first. Then move to injectors. I'm sure vacuum is your issue.

Reefin Dude

i thought the 30ff code was a sign that the waste gates were leaking. time to replace the turbos.


G~

NoQuarter

There are many reasons for an underboost diagnostic code. Needing new turbos is the least likely.

535Paul

Here is a log from rolling about 40 in 3rd gear, WOT until around 65 when I got reduced power warning. I noticed that bank 2 is running in the 30's compared to bank 1 being around 14

Click Here: Data Log