Z4 e85 N52B25 oxygen sensor problem

[Scarp]

Hi ,

Maybe you guys could help me recently I am having problems with oxygen sensors and somehow cant solve it. The exhaust is completely remade but the main idea how the car was made remains. There are still 2 sensors before the CAT and 2 sensors after the cat.

I changed the rear oxygen sensor and the problem was fixed for some time .

2 months ago the check engine came up and writing a front oxygen sensor changed it a week later I changed the second front sensor and now after an hour of driving I got it again.

Cant believe that 3 sensors broke in 1 month time . After I changed the rear 3 months no problem . There are sport catalysts but I drive the exhaust for like 2 years withou any problems . I bought the last 4th oxygen sensor but I am wondering why it writes the front one now aswell.

Any idea how to help ? the front ones are ogiginal cables the rear ones are after the cat and the wires were extended by the company that built the exhaust .
The car runs almost normal no vissible change

 

[ph001]

The fault codes point more to a wiring problem than the sensors themselves. The heater connection can be tested easily with a multimeter, they should measure <10 ohms

 

[rally-chris]

If you replaced a sensor, did you fit a genuine part or aftermarket? When I had my Scorpion exhaust fitted to my coupe I had a failed post cat O2 sensor, and my garage tried two aftermarket sensors only for the MIL light to come on again within 10 miles or so. In the end they sourced a genuine BMW sensor and the problem went away. The N52 ECU seems to be sensitive to O2 sensor type.

Chris

 

[Scarp]

I used bosch sensors never heard anyone had problems with them but it can happen

 

[Scarp]

Voltage of on of the sensors seems strange but that one I cahnged after making this video

[youtube]https://www.youtube.com/watch?v=SprrFBY7hs4[/youtube]