P0125 in 1997 Toyota Landcruiser after cleaning sensor and replacing the gasket

Question

I had to replace the gasket under the #1 O2 sensor in my 1997 Toyota Landcruiser. While the sensor was out I cleaned the tip via the holes using acetone and then a strong detergent and rinsed well with water. I also cleaned the vent holes and harness connectors using electronics cleaner. I know, people say don't clean sensors but figured what the heck, it has high miles so if I kill it I'll just replace it.

But the strange thing is that I got P0125 code after driving just 6 miles after shutting it down, restarting 5 imnutes later. I checked with a hand held scanner; coolant temp was reading as it should, 187-190'F, exactly where it should be. The #1 O2 sensor was flat (voltage not moving up and down) and the system was still in OPEN Loop.

Answer 1

Diagnostic procedure says use the toyota computer and check the voltage on the oxygen sensor with the graph. You might be able to use a regular obd-II that can read oxygen sensor voltage

it will either be a bad oxygen sensor, wiring issue or the computer is bad.

 

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