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Toyota Repair/Corolla 1994 1.8L


Hi Ted,

The "check engine" light come on and I suspect it's the oxygen sensor. Using a multimeter to check for voltage and I'm not getting any. Any fuse/relay controlling power to the o2 sensor.

I did the manual diagnostic and came up with code 25 (using check engine light).

Please advise and thank you in advance


Are you using the diagnostic check connector under the to check the voltage, the meter should be connected to terminals OX1 and E1 while the engine rpm is kept at 2000, with the engine warmed up, this assures that the system is in "closed loop" which is when the sensor is sending feedback to the ECM. At that time you should see a fluctuating voltage of about 1 volt positive to negative.

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Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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