Date: Mon, 27 Aug 2001 23:35:42 -0400 From: Fred Hess <surffnopsambeyq.arg> Subject: Re: O2 sensor & black smoke?
On 27 Aug 2001 10:45:10 -0500, dhinznopsamh.execpc.com (Dave Hinz) wrote: >Fred Hess (surffnopsambeyq.arg) wrote: > >: All the speculation going on that a simple VOM could test (o2 sensor), >: but I digress. Wouldn't failed signal from the lambda sensor trigger >: the ECU to believe the engine was running lean? Wouldn't this signal >: create a rich running vehicle all the time? > >Fred, > >Do you have the testing mode for the O2 sensor handy? I can't find my >book - hot, or cold, and what resistance should I measure where? > >How can I tell if it's good or not? I never measure resistance. Try this.. OK.. here's the simple method I have used. I warm the vehicle up. I should mention that you want a DVOM to test with. You want the vehicle in closed loop. Then I look for changes in voltage. I'm looking for .2 to .7 volts. When the engine is turned off I'm looking for .1 or less immediately. If there isn't a constant change in voltage, or if it sticks high of low, your sensor is no good. The voltage you want to measure is on the signal, not the lead that preheats the sensor (in 3 or 2 wire sensors.. they send 12volts to the sensor). It' works for me. I haven't priced the Bosch replacement lately but can't imagine it costing more then $50.00. I wouldn't buy this from a Saab dealer. I would replace it only with Bosch equipment.