Either its bad, disconnected, or grounded. Check the voltage on the O2 with a voltmeter at the connector after unplugging it from the ECM with the engine running so it gets warm. Or take it out and heat the end of it with a propane torch and put a volt meter ground on the case and the positive on the pin in the connector. Once it gets cherry red, you should start getting a reading if its good.
If that works, check the wiring in the car. If thats too much work, just replace it and see what happens. If you still have 000... check the wiring to the ECU. Does the scanmaster work normally otherwise?
