I've owned my fd for over a year now and have experienced quite a few different problems thus far. My car has:
t-62
PFS SMIC
Apexi PFC
Support mods

Today after driving to an interview roughly 30 miles away, I get back in the car afterwards and drive maybe 100 feet and the add coolant buzzer starts going off. I looked at the water temp via PFC and it read 85 degrees. Immediately I pull over and check the dipstick from the coolant fill, and all was normal. So I fill it with water until the overflow opens on the radiator (about 1/4 gallon) and the alarm is still going off.

So I just said the hell with it and began driving again, figuring their was nothing else I could do. Maybe 1/8 mile down the road the buzzer goes off.

Does this mean anything? I figured something like this would be the result of something fowling up with the ECU. Can anyone confirm?

 

you don't have to be overheating for the low coolant idiot light to go off.

 

I know thats not the only possible reason. I've heard of cases where you could be on a hill and the flow to one side will cause the alarm to go off

 

The PFC reads from the 2 wire factory water thermosensor on the water pump housing. The factory coolant gauge reads from a different one wire sensor. The low coolant buzzer is yet another sensor that is located in the radiator.

 

actually the FD low coolant sensor is in the waterpump housing... but filling the overflow tank wont fill the system till it cools down and sucks the coolant back in. you need to fill at the waterpump housing. and only open it when cool or it will spray boiling colant everywhere. this issue can be caused by a dirty radiator cap with a small piece of dirt or flake of rust getting in the draw back flapper in the cap keeping it open so the coolant expands when hot into the overflow tank then cant suck back when cool as there is no vacuum in the system as that valve/flapper in the cap is stuck open. overflow will show good but not the system. common problem. and as stated the buzzer has nothing to do with the PFC

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