voltmeter and a propane torch.

Remove o2 sensor and secure gently at the nut in a vice

place the pos. lead into the o2 output wire and ground the other lead to the o2 sensor nut.

heat the end of the o2 sensor with propane torch, it should get red hot. Now move the propane torch up and down the sensor tip so the flame goes on and off the sensor tip. Watch the voltmeter it should switch rapidly back and fourth as you move the torch over the sensor tip between .2 and .8