O2 Sensor Heater Problem

Okay, so I'm getting the codes for an O2 sensor heater problem. Check the fuse, replace it, its blows right away. So I take some readings, same voltage as battery with key on on one side, of course none on other of fuse clip. Turn key off, take resistance readings, on sensor side its like 4 ohms to ground but on power side (12v side) its like 10 ohms to ground. I un plug all the sensors and it readings stay the same. All the wires near the plug look okay. The readings should be Infinite to ground shouldnt they or am I wrong?

Will one of you pull your O2 sensor fuse and take some readings for me?

If mine is just all messed up I think that I'm just going to run a new wire for power and just attach it at the plug.

Thanks, and please, somebody take some resistance readings for me.

That fuse powers up all three oxygen sensors. Did you disconnect all three? If that didn't help, try disconnecting connector C100 (six wire connector next to the AC accumulator on the fender side). Terminal E circuit 539 is the feed from the fuse to the oxygen sensors. If the fuse blows, the short is between the fuse box and that connector. If not, it's between the connector and the sensors.

I disconnected all three with no change. I'll try the main plug thing. Is there a way to explain the 15 ohm to ground reading that I get on the power side fo the fuse clip? What does yours read?

Check the wires going to all the O2 sensors.

Sounds like one of them has a wire that might have worn through its insulator and shorting out.

Hey maybe you guys can help with another o2 sensor issues I am haveing.. Please see the http://www.automotiveforums.com/vbulletin/showthread.php?t=1070286 to see what i have been dealing with thanks..

Alex

If you like, I’m available to look into recall/warranty information on your vehicle for you. Please private message me the last 8 of your VIN and I’d be happy to help!

Sarah
GM Customer Service