[gianlatm240]

I have had a jb4 in my m240 for over a month now and recently installed a *** less ********. The install went without any damage to both O2 sensores but for some reason got these fault codes. I decided to revert back to the Oem ******** but still fault Codes are present

12B104 O2 sensor before *** disconnected
12B304 O2 sensor after *** disconnected
12B102 Lambda probe heating before Catalyst Activation: Short Circuit to Ground
Again I removed the O2 sensors before anything and put them in a safe place. The last time i installed a ******** used the car with out anything going wrong untill 2 months later with the same situation. Had to take it to the dealer and ended up in a full DME replacement. That being said the O2 sensor may have been damage du to bumping into things.
Any help Is appreciated.

[Payam @ BMS]

They're both connected up top of the engine for sure? Those codes are very random.

[gianlatm240]

Yes, have checked a few times. When the car is in ignition mode, it only shows the 12B104 code and the CEL goes away. But if toy stop and re-start the car all codes come back and CEL comes back.