07 Impala LT 3.4 engine hot/ac off

Hey everyone.
I have an 07 Impala LT (3.4 Flex)

Intermittently, I get a dash code saying my engine is hot, and the AC is off (engine hot/AC off) and sometimes it hangs long enough to kick on the MIL.

But most times it just starts working and shows temp. I figured bad sensor. But running the Torque pro app, and connecting to the ECU actually shows the coolant temp, despite the gauge on the dash showing nothing and the error code I mentioned. The fan by default runs the whole time this is happening.

I have the sensor, and I guess I'll replace it just to eliminate one possibility. But is this a known thing? My searches have really only shown the sensor as the culprit.

Appreciate any ideas.

AG

If the pcm sees no temp input, it goes into a default response , it assumes the worst, turns on the fans and the warning lite, so replace it and check all related connections.

If the pcm sees no temp input, it goes into a default response , it assumes the worst, turns on the fans and the warning lite, so replace it and check all related connections.
I get that. But why would my Bluetooth ECU reader see a temp if the ECU doesn't. I mean, it's showing me data in real time with the engine running. And it'll go a week just fine, then throw the error for a couple days, then back to not working. BTW, I checked coolant level immediately, and made sure it wasn't actually overheating. I have not checked connections. I'll do that when i replace the sensor. Thanks for the answer

That vehicle may have 2 temp sensors, one for the pcm one for the temp gage, check into that.