71Stang

Hello Guys,
My 2006 Acura RL is sending "Check Radiator System" notifications. Some troubleshooting has shown:
1. Each time this happens, the radiator fans are off while the coolant temp is around 180F and even higher.
(I believe the passenger side fan is triggered by the AC system and the AC system is off, so that one may not have anything to do with it).
2. The NAV system datalog screen shows trouble code P1152. This code sets about the same time the instrument panel throws up the Radiator System warning.

Question: Does anyone know what this P1152 code means? I'm hoping it helps me narrow it down to what exactly is keeping the fan from running - i.e., some control unit, some sensor or the fan motor.

BTW, I'm assuming the fan should be on by the time coolant temp reaches 180F. Maybe I'm wrong there? It is winter time and I have seen the coolant temp go up to about 200F and the fan still not on.

Thanks in advance.