MAF sensor wiring S70

1998 S70 T5 and I've replaced the MAF sensor with a part from another
car that it is known good.

Yet, I still get a check engine light after driving for a while so
definetly not the sensor.

Is that harness often faulty?

Is it easy to replace?

Anything else that's a possibility?

It may be heat related the way it's acting and I saw on some earlier
cars there is a thermostat that controls the air filter temp?.....but
see nothing like that on my 1998.

Appreciate any thoughts. Thanks.

Also, has anyone seen the "altitude" or barometric pressure sensor go
bad?

The code I get actually refers to this part but like I say, the check
engine light will go out with the MAF sensor cold and
the battery disconnected.

I can run for days/hours before it comes back on -- unpredictable.