Let me make sure I'm following you correctly. When you do the test described in
this post you get infinite resistance?
If that's the case, I'd think that would indicate the heater circuit is broken somewhere in the sensor.
If you can, I'd return the universal sensors and get the OEM sensors. If the universals are wired correctly (sounds like you're confident they are), and if the sensors didn't change between 2001 & 2002 (doubt they did), the resistance should match the specs in that post. If not, they're not going to work.
If the sensors do test good and the error returns after being cleared, I'd say you have a problem with the vehicle's electrical system...