• Tiny
  • bruce farris
  • 2000 Toyota Camry

Computer problem
2000 Toyota Camry Front Wheel Drive Automatic 105, 00 miles

Electronic Diagnostic Test results:
Catalytic Efficiency Part #PO420 and EVAP Emission Control System Part #PO446. Are these two parts related to engine performance? How urgent is the checking or replacement of these two parts?

Bruce Farris

Do you
have the same problem?
Tuesday, July 29th, 2008 AT 6:23 PM

1 Reply

  • Tiny
  • rasmataz
  • Member

Not related

P0420 Catalyst

A code P0420 may mean that one or more of the following has happened:

Leaded fuel was used where unleaded was called for
An oxygen sensor is not reading (functioning) properly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Possible SolutionsSome suggested steps for troubleshooting a P0420 code include:

Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
Inspect the downstream heated oxygen sensor (HO2), replace if necessary
Replace the catalytic converter
One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into

P0446 Evap System
Problem with the vacuum switching valve

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Tuesday, July 29th, 2008 AT 6:40 PM

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