Your cold start sensor is your engine coolant temperature sensor. The actuator is the idle speed control.
Testing the coolant sensor:
Read resistance on multimeter between pins 1 and 5 on ECU.
0c = 5700-6300 ohms
10c = 3600-4000 ohms
20c = 2400-2600 ohms
Testing the ISC:
On the ECU you should have about 3V on pin 4 of the ECU when the car is at idle.
Pin 1 should have zero resistance to ground when the car is at idle.
To further test properly you need an oscilloscope.
