[E90owner11]

Car: 2007 320i E90 N52
Been having trouble with a persistent rough idle, stall upon coming to stops at lights or reversing issues for a few months with no fix in sight no matter what I do.

Here’s the current codes:
002C72 : Digital Motor Electronics (DME), catalytic converter downstream oxygen sensor 2

002C9C (ABSENT) : Digital Motor Electronics (DME), catalytic converter upstream oxygen sensor heating

002CA0: Digital Motor Electronics (DME), catalytic
converter upstream oxygen sensor heating

002CA9:
Digital Motor Electronics (DME), catalytic
converter downstream oxygen sensor heating 2

I’ve done almost everything I can think of for this issue and the various mechanics I’ve seen are clueless.

Replaced all 4 oxygen sensors, Catalytic converter, MAF,
Air Filter, Vanos Solenoids, Battery, Spark Plugs, Starter replaced, Alternator replaced, Ignition coils replaced, Vacuum leak tested

Some of these ‘fixes’ listed are just unrelated extras in case anyone may think they correlate to my issues.

I’m so clueless on what the fix is and I’m losing it as online advice varies (it’s Vanos, MAF, O2 Sensors, PCV)

Please can someone suggest some possible reasons for these issues? The mechanics suggested to replace 02 sensors and the issue still didn’t go away, they suggested the cat and the issue still stands.

Thank you

[E92_William]

First thing I would go to https://fuse-box.info/ and check what fuse runs the heaters for the o2 sensors in your car given your build date.

Best thing would be to run a test plan on ISTA and go through the steps on it and see what options it gives you as to fix the issue. I’m guessing clogged cats could get bad enough to the point the engine can barely idle, I’ve seen clogged air filters on cars to the point the thing would have about the same symptoms you have here. When I had a clogged pcv in my 328 the car did all of this and a whistle sound when letting off at speed except for the o2 codes.

Can also check if anything is in the intake track like a rag or something but since there are o2 codes it’s likely at the exhaust side.

Also on the N52 from my experience when you remove the intake manifold you have to be careful so the wires for the o2 sensors don’t get caught between the intake and the cylinder head when installing it back, it’s not uncommon for them to get caught by cylinder 6 when installing the intake and having codes for the o2

[NZE90]

Your engine can't be an N52 if it's a 320i. Can you confirm exactly what it is, then i can post a wiring diagram for the o2 sensors.