How can I tell if my o2 sensor is bad?

 

The is no good way to really know for sure. You can try probing with with a voltmeter but if you have to know which pins NOT to short together -- and even then it could read fine even though it's going bad. How many miles do you have on your car? If you have over 90k the chances are it is bad or on it's way there. Once they get really bad they can flag the Check Engine Light too.

 

You can test the o2 with a voltmeter, I will tell you how.

Your o2 sensor reads 0-1 volt. It creates its own voltage. On a 4-wire o2 sensor, the o2 sensor wire that goes to the ECU (pin C18) is the WHITE wire. Take a voltmeter, or a multimeter set on DC 20 (Direct current, lowest voltage setting), and jab the red probe through the insulation on the white wire, touch the black probe to the (-) terminal on your battery. Watch the needle on the voltmeter. If it cycles up and down from 0-1 volt while your car is idling, it works.

The other alternative is to buy an Autometer Air/fuel gauge. It works off of the voltage from the o2 sensor wire. For installation, you need power, ground, and the last wire splices to pin C18 at your ECU. Really simple install, and the gauge is less than $60 if you shop around. There are cheaper ones out there, too, but the Autometer works really well, and will not only tell you your o2 sensor is working, but how rich or lean your car is running. A great tool for people with fuel economy issues, or for boost junkies.

:thumbup:

 

... and if you had a failure on your o2 sensor, you'd get a check engine light with either code 1, or code 41. It's not common for these to fail without triggering a CEL, but it's not impossible. If I were you, I'd check to make sure your IAT sensor, MAP sensor, TPS sensors are hooked up properly. Your car would run like total ass if either of those weren't hooked up, but those are the only 3 sensors in that area. Then maybe inspect your vacuum hoses for holes.

 

How much do o2 sensors usually run if I had to replace it?

 

60-80

 

Appreciate it.

 

That is for a universal one -- meaning it doesn't have a connector that snaps right to your stock connector. You have you splice in the wires but it comes with something (at least the Bosch one does) that allows you to do this without soldering. To get one that, out of the box, will plug right up to your stock connector will cost $150-200.

Also keep in mind these O2 sensors don't always come out easy. Mine broke off even after I soaked it several times with liquid wrench (and waited 20+ minutes for it to soak in good). I've heard heating them helps to get it out easier -- but I was told you needed to get the metal glowing-hot which takes a helluva torch.

 

also you might have a "soft" code in your PCM. Its just like another code but it doesn't set the MIL (check engine light). go to autozone or something and see if they have the scan tool for your car. usually they will let you borrow one and check it out.

 

Appreciate the help yall!