Faulty O2 sensor??

[Corrosio]

Hi. I have the BMW e46 318i, engine N42 B20 (143 hp).
I suspect on the faulty o2 sensor 2. I need just your opinions.
At combusting a stoichiometric fuel mixture (Equivalence Ratio: lambda = 1) in a closed loop, the output voltage on the o2 sensor should be approximately
0,450 V to 0,500 V (when ist lambda = 1; ratio Air/Fuel = 14,7 : 1) at operating temperature.

But what if is lambda = 1,005, this is optimum; output voltage from o2 sensor is 0,655 V, when STFT-B1 = -0,8% and LTFT-B1 = 2,3%, MAP + MAF work correctly.
Then fuel system status CL switches to OL-Drive, when STFT-B1 = 0% and LTFT-B1 = 2,3%; output voltage from o2 sensor: 0,025 V, ( 2775 RPM),
lambda = 1,999 (ratio Air/Fuel)

Ideas? Opinions?

[MarcoZandrini]

What year is the car? BMW switched to a different O2 sensor in model year 2003. Also, you need to scan the engine computer for codes.

[Corrosio]

Hi. My BMW made in the year 2004 (January)

[MarcoZandrini]

I believe BMW switched to wide band O2 sensors for 2004. They operate differently than the old 4 wire narrow band sensors.

[dhurley34]

Sometimes low (lean) downstream o2 voltages can be from a failing catalyst or a defective sensor. I would begin with replacing the sensor. As marco noted, BMW changed their sensors sometime in the 03-04 production, so find the part number specific to your VIN on RealOEM, cross reference it, and only buy a Bosch sensor.