Hi, i have a 1993 2.5L flex fuel dodge spirit with only 27,000 miles. This car has recently developed an overheating problem. I replaced the thermostat and to no avail, my car still is overheating. I thought it might be the coolant temperature sensor because my fan comes on just before i think my car is going to explode. ANY WAY i took the spirit to autozone and had it scanned. The scan detected that the PTU solenoid was malfunctioning. SO.. i bought a repair manual for it and ran a self diagnosis on it and 2 codes showed up... code 12: problem with stand-by memorycircuit. Direct battery input to controller disconnected within the last 50 ignition key-ons. & Code 37: Torqe converter unlock solenoid circuit. An open or shorted condition detected in the torque converter part throttle unlock solenoid circuit(auto. transaxle models only).....   So altogether how do i get these two codes fixed, how much will it cost and are they related to the overheating problem? Can you help me Please?

Optional Information:
1993 Dodge spirit 2.5L flexfuel4c

Already Tried:
thermostat spark plugs air filter