O2 Sensor Codes Still On

[zeppelingto]

I just bought a 2006 Sierra pickup 2wd with the 4.8 Vortec. It's a great truck with a lot of power, but I bought it with a CEL on. Got home and ran the codes to find it needed a new EVAP canister (I saved $100 on the part thanks to this forum recommending ordering the part from a suburban instead) and 4 o2 sensors. I replaced everything and it still gets the code for the o2 sensors. I checked all the connections and reset the light and it still comes back on. The codes say that its the circuit or connection but everything looks fine. I sometimes hear a whining/whistling sound that I thought might be a vac line leaking? Any suggestions?

[txab]

What is the code # you're getting?

[desrtrat]

but I bought it with a CEL on. Any suggestions?

never buy any vehicle with a CEL light on...

[zeppelingto]

Codes are p0060, p0056, p0036, and p0054. Last 3 read "oxygen sensor heater condition-check repair resource for sensor location identification. The power control module controls the electrical circuit for the oxygen sensor heater. The computer has recognized a failure in this circuit.

Probable cause

1 - check circuit fuse.

2 - Relay defective.

3 - check circuit wiring."

 

The first says pretty much the same thing, but lists bank 2 sensor 2 and gives the same probable causes and adds it could be a bad ecm.

[zeppelingto]

I'm gonna try to trace all the wires and look for any problems there. I'll check all fuses again. Does anyone know how to check the circuit for the o2 sensor? Maybe any pics or diagrams? I have a friend who had the same problem in a 2005 and it turned out to be a bad ecm. I'll keep you updated with any developments, but any advice is a great help.