Can you test a O2 and MAP sensor?

Just curious.....what to look for and how to do it?
Brett

You'll need to measure the voltage from the signal wires of each sensor to the ECU with the engine running. The signal wire of the MAP sensor is the middle one of the three. The O2 sensor has four wires. One will be 12v power to the heater element, the second will be heater element ground wire, the third will be a sensor ground, leaving the fourth as the signal wire (0.0-1.0v).