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1997 Toyota camry V6

I am seeing a check engine light on since last few days in my 1997 camry V6. I went to local mechanic and he peformed a free scan in front of me. It is showing up 2 codes P420 and P1780. The mechanic mentioned following probable problems for these codes.

P420 - Catalytic converter is bad or O2 sensor could be bad P1780 - Park N. switch could be bad or the car computer could be bad.

The mechanic is saying he would charge $145 just to find out the exact problem.

Can somebody please guide me how I can find out the exact problem with spending less $?

Thanks Mohan

Reply to
Mohan
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A Toyota dealer will diagnose the problem without charging you. Most likely cause is O2 sensor.

Reply to
Mark A

P1780- Short in Park/Neutral switch circuit or bad switch. The computer is detecting the switch is ON during driving or is giving an indication of being in two gears at once.

The 0420 code is stating the converter is not functioning as it should based on the signals from the 02 (or A/F sensors) before and after the cat. The cat could be bad, one of the sensors (02, A/F), exhaust system problem.

The service manual at the link below provides a great amount of detail on these codes. Download the Gen_4, Diagnostics Section. The Toyota dealer should be able to run down the problems using their hand held diagnostics tester.

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Reply to
toyomoho

Reply to
Mohan

Oxygen sensors can only be accurately tested in the labs. The sensors can go bad and not set sensor related codes. Denso heated oxygen sensors since 1997 have cost Toyota, Honda and many owners $$$$$ on ruined catalytc converters.

Assuming you don't have exhaust pipe leaks or other tuneup related problems and the converter works (not falling apart on the inside, able to reduce emissions to the very low end of the range, etc) then it's most likely the sensors. I know because with Bosch planar sensors I managed to rid a P0420 problem when TSB recommended $800-1000 cat replacement.

If you need sensors, go with the best in class Bosch.

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The Bosch universal type for this application is $75 each (if you isolate it to the sensors you should replace all three) but requires splicing the old connector onto the new sensor. But it's the excellent planar type that resists contamination much better than the outdated Denso thimble junk.

Planar design:

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Mohan wrote:

Reply to
johngdole

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