My 07 SE will randomly throw codes, 'general cooling performance' and 'thermostat regulating temperature'. The fan will kick on and I'll lose my temperature reading on the dash, just drops to no temp. I'll see a red lightning bolt dash light come on as well.

No other symptoms! If I turn the car off and start it back up, boom, problem is gone! The temp gauge will read normally(not overheating), the fan isn't stuck running and the red lightning bolt is gone!

NO leaks, NOT overheating, thermostat and thermostat housing have been replaced, temp sensor replaced. Also A/C isn't working now, that related maybe??
Any ideas??

 

If your coolant temp sensor goes OPEN ckt, the PCM will default to running fans at all times. That same sensor is also the info for the gauge to use.


I would be looking at the sensor wiring for starters. The connector may even be corroded.