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Toyota Repair/2000 Toyota Solara check engine lite


Had a P0420 and P0330 code and Ted Ritter suggested I "front converter directly after the exhaust manifold"

Before I replaced the front converter, I replaced the EGR valve and the EGR transducer and cleaned the port at the bottom of the intake throttle valve and cleared the check engine light.In a short period od time the light was back on. Then I went ahead and replaced the front converter as suggested and I replaced the next exhaust pipe with catalytic converter. At this time also replaced the air cleaner intake tube and resonator as these were brittle and had cracks in them. this managed to last the longest, 2-3 weeks but now the light is back on with a P0420 code (catalyst system efficiency below threshold bank 1)

As of now I have done nothing with the O2 sensors or the EGR vacuum solenoid. I had another suggestion to reposition the throttle position switch by removing it's bushing  to gain a slight adjustment, which I have not yet done.

I would appreciate any suggestions on the next best option to try and correct this. Not sure what the likelihood is of a bad ECU.

Thanks, Joseph Caroccia

I would recommend that you have the cat converter tested using a diagnostic scantool that can read live data from the A/F ratio and O2 sensor, this would indicate if the converter is working or not and also test the O2 sensors for proper operation by reading the voltage values, you could also elect to just replace both sensors but it does not have a specific code for those, it's possible that an aftermarket converter if used did not meet Toyota's requirements.

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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.


Toyota technician since 1979,expert in electrical systems,OBD systems,engine repair, driveability problems,EFI systems,ASE certified,Toyota master technician.
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Toyota master technician, ASE certified in eight catagories, Hybrid vehicle certified. Toyota technical training: Engine Automatic transmission Manual transmission Drivetrain Electrical systems Brakes and chassis Air conditioning Engine performance and diagnostics Hybrid systems

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