Heater Core Malfunction(02 sensor)

[Lt.Leggs]

Ive been trying to get my 98 mountanier inspected but it wont pass because the code for a heater core malfunction. But the problem is that when the code comes on it goes right back off and then the obd2 test has to go again and then the code comes on then back off again and repeats that cycle. I changed the o2 sensors already and all i can think is its a ground wire but i cant find where it is.

 

[Lt.Leggs]

Any help with where the ground wire is or anything on what you may think it could be would be appriciated.

 

[RomeovilleIL]

What is the actual engine error code number?

 

[Lt.Leggs]

po141 and po161 There both the heated o2 sensors and its the one on the left after the cat and the one on the right after the cat.