What To Do 2004 Gs300

[04lexus]

Hi

Very nice web site.

Had my sedan for five years third owner 177K miles runs great, but needs some more work. Just spent 700.00 bucks having the HVAC servo deep in the dash replaced. That works fine now as advertised.

The engine light has been on for some time now. I took the car to the DMV and it failed inspection of course, and gave me the following diagnostic report:

The fail code on the DMV report says: "Diagnostic Trouble Codes: P0031 HO2S Heater Control Circuit Low Bank 1 Sensor 1.

The Advance Auto techs said the sensor closest to the front of the block on the exhaust manifold was the bad part, so I replaced with a Densor factory part. I did that and removed positive battery cable to reset the engine light, and ten minutes after running with the engine light off, the engine light comes back on.

Did I replace the wrong sensor? It says "heater control circuit."

Thanks in advance for any help.

Jim