repair oxygen sensor

You need to replace it. It is not a simple task, unless you do some research on how to do it.

wp51 wrote:

========================= That's an interesting question. Answer is probably not. For example, a common failure mode is for the heater to fail. The heater heats the oxygen sensor so it can begin working sooner on a "cold" engine. The heater uses a filament like an incandescent light bulb. Your chances of repairing that are probably about the same as repairing a burned out light bulb in your house. Another thing that can kill an oxygen sensor is using leaded gas (very unlikely) or using standard silicone sealer around the car where the fumes during cure get into the port on the oxygen sensor open to the atmosphere. That kind of damage is not repairable either. The third reason for decreased performance from an oxygen sensor is that they "get lazy" over time. For this reason some people recommend replacing them on a mileage basis but when I've done this on other vehicles in the past I noticed zero improvement. The simple first generation O2 sensor in my Camry (which is supposed to last a shorter time than the newer sensors) is made with a zircon material over ceramic. Both of these materials are able to withstand very high heat - I've forgotten the exact operating temperature but I believe it is well over 1000 deg. F. The zircon is like the cubic zirconia material used in artificial gemstones - very hard and very durable, yet at the same time, oxygen gas is actually able to permeate (pass through) this material generating a small amount of electricity. So the oxygen sensor functions to measure differences in oxygen content between the exhaust stream and the outside atmosphere. My guess, my theory, my conjecture, is that unburned hydrocarbons aka "carbon" in the exhaust coats the oxygen sensor over time causing slower response time aka "lazy sensor." I suspect this type of carbon accumulation might be more common in an engine not in peak operating condition (for example oil leak down past valve seals causing oil burning on start up) or excessive idling in traffic rarely "opening up" the throttle with engine at operating temperature. Toyota's method of testing an oxygen sensor for my model is to connect an analog voltmeter and count the number of times the needle swings in a fixed number of seconds. If the voltage fluctuates rapidly enough, the sensor is good. Now I use Redline complete fuel system cleaner a detergent "which survives the combustion process" and "cleans emissions control components," have also run a quart of distilled water sprayed into the intake on a hot idling engine to remove carbon in the combustion chamber by converting the H2O to H2 (hydrogen gas) an CO (carbon monoxide), and when I change the timing belt I also change the spark plugs, wires, cap and rotor, plus I ran a one time treatment of "auto-rx" (auto-rx.com) to remove carbon from the piston ring lands, plus I use Lucas heavy duty oil stabilizer with Mobil 1 synthetic 5W30. The ash content of any engine oil burned can contribute to O2 sensor fouling. The result is, that when I removed the exhaust pipe to change the engine oil pan gasket and looked inside there was no black carbon to be seen, the oxygen sensor looked nice and clean and testing with the meter showed normal operation at 150,000 miles, plus the smog testing showed O% oxygen content at the tailpipe. So if your oxygen sensor was simply "lazy" from carbon accumulation, you could try very carefully holding it in a vise, to avoid cracking the fragile and brittle ceramic shell, and heating it to operating temperature with the flame of an oxy acetylene torch to burn off excess carbon. If the sensor was already "bad" you wouldn't have much to lose. Then re test and replace if needed. This is all just a theory, haven't tried it (haven't had the need) but I have seen O2 sensors heated that way to test for voltage production. In the end it is probably simpler to just replace it with a brand new one, but you did ask about repair, so there you go.