Code 29F5

[Buster1949]

I replaced all four O2 sensors on my 2011 328i but can't fix 29f5, what should I do next ?

Signal, Oxygen Sensor, bank 2 after Cat is swinging from .74 v to .06 v ? this drops off in one reading to .06 and then returns in a couple of seconds to .74. The old o2 sensor was indicating the same dips as new sensor .
Signal, Oxygen Sensor, bank 2 before Cat reading 1.93 v to 2.07 v

Bank 1 before Cat 1.96 v
Bank 1 after Cat .72 no sudden dips

Does the above dips on bank 2 after Cat indicate a plugged or damaged Cat ?

[154e90]

I replaced all four O2 sensors on my 2011 328i but can't fix 29f5, what should I do next ?

Signal, Oxygen Sensor, bank 2 after Cat is swinging from .74 v to .06 v ? this drops off in one reading to .06 and then returns in a couple of seconds to .74. The old o2 sensor was indicating the same dips as new sensor .
Signal, Oxygen Sensor, bank 2 before Cat reading 1.93 v to 2.07 v

Bank 1 before Cat 1.96 v
Bank 1 after Cat .72 no sudden dips

Does the above dips on bank 2 after Cat indicate a plugged or damaged Cat ?

At idle the engine should switch between running lean and rich for emissions purposes because it keeps the cat working in an optimal range. You should see that on the pre-cat o2, but not on the post cat o2. The cat should smooth it out if it is working. I would expect to see a flat value on a post cat o2 signal if the cat is good. A cold cat doesn't do anything so you should let the cat warm up and look at the values again before calling it dead.

If the car can rev freely and doesn't have issues running you don't have a plugged cat.

I have both N52 cats for sale if you happen to be in SC anytime soon.

[Buster1949]

the bank 2 after Cat dips are with a hot cat at idle.
the engine runs great with lots of power.

Should I reset the DME cable connector, just wondering if a bad connection could cause the dips ?

[154e90]

the bank 2 after Cat dips are with a hot cat at idle.
the engine runs great with lots of power.

Should I reset the DME cable connector, just wondering if a bad connection could cause the dips ?

You can try re-seating the o2 connectors near the valve cover but I doubt that's it. I wouldn't go in the ECU box to touch any connectors, those are extremely robust and likely aren't your issue. Can you post a photo of the signal you're getting? I suspect your cat is bad.

[jclausen]

Is this fault the same as catalytic converter efficiency if so the cat is bad

[Buster1949]

686018

[Buster1949]

686018

Reset 29F5 yesterday and drove the car 95 miles. The Service Engine Soon light did not come on. I checked it with my code scanner and the 29f5 was indicated so I drove it another 5 miles and the SES light came on. The engine runs great with lots of power, the Cat 2 might not be working but it is not plugged ?

[jclausen]

If it’s an efficiency fault it would been the cat is not processing the exhaust correctly the post cat o2’s job is to monitor what is coming out of the cat