1998 S90 no voltage from o2 sensors

[1998S90]

Front and rear o2 sensors are showing no voltage from live data from any scan tool I've used. CEL on with codes for no voltage from either sensor.

Measuring with a multimeter, at the harness connector under the hood, there is voltage coming from from the o2 sensors. I have not yet measured directly at the ECU.

The heaters on the o2 sensors are working, voltage present, no errors.
Currently stuck in Open Loop, Sys Fail.
I tried leaving the battery out for days, cleared the CEL with scan tools. It doesn't seem to even try to read the o2 sensors anymore. Stays in Open Loop.

Any chances this could be a bad ECU?




I looked at a post I made back in March on here, but I wasn't aware that anyone had replied, and the conditions seem to have changed, so I made a new post. (I'll try to find new post notifications)

Background: I've had this car almost a year, although just within the past couple of weeks started driving it and trying to work out the bugs. I did tinker a little with it earlier this year, but it got put on the back burner. I do not have VOL-FCR.

-New battery installed.

-EVAP system is leaky, and will be repaired if I can get the o2 sensor issue resolved. For now, the vacuum to it has been capped off.

-Several vacuum lines replaced.

-Both o2 sensors replaced, even though it was clear they had already been replaced fairly recently prior to me acquiring the car.
(universal o2 sensors were used, yes I read all about the problems with them, however I am getting voltage from them past the connector, so I know they are working.)

-Just learned about testing the PCV system by pulling the dipstick and looking for smoke, mine needs replaced.
Front lower control arm bushings are shot, driveshaft center support bushing is shot, either one inner tie rod or the rack is shot.
-Brakes rebuilt on all 4 wheels.

The body and interior are great. I like the car.

I bought the car in a no-start condition for really cheap, the owner had to move. A solenoid wire repair, fuse replacement, and new starter got the car running. It ran very poorly until I capped off the bad vacuum lines. It actually runs pretty smooth now, although it is very sluggish on acceleration. Understandable with the o2 issue. It seems like I could drive it for a long time in the condition it's in, I just prefer to try and fix what's broken.