1997 Toyota Camry engine code P0420

Tiny
MIKE44LABREC
  • MEMBER
  • 1997 TOYOTA CAMRY
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 152,000 MILES
I love reading your site and now it is my turn to ask you for advice. I have a 97 Toyota Camry 4 cyl with a code of P0420 Catalyst Efficiency Below Threshold (Bank 1). A couple of years ago I had this code come on and a dealer said I need to replace the exhaust manifold/convertor. I did this and they cleared the code. Later on it came back and I installed the first O2 sensor because the old one was re-installed. Now it comes on and goes out at no particular time. I know that the second O2 sensor was changed at a service station since then but I don’t know if it was factory brand, if that makes a difference in this case? Could it be as simple as a connection problem? Should I use contact cleaner on the O2 connections, erase the code and see if it comes back? The car runs excellent and no difference in mileage. I am stuck on what to check and/or replace. I look forward to your response and once again, you’re doing a great job with the column.
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Saturday, May 16th, 2009 AT 8:54 AM

3 Replies

Tiny
JACK42
  • EXPERT
Its always best to use OEM parts, especially when it comes to emissions/sensors. Definitly make sure the connection is clean and tight.I take it the engine runs smooth? No misfires or other driveability issues? Clear the code and see if it comes back, this is always a good practice.
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Saturday, May 16th, 2009 AT 9:04 AM
Tiny
MIKE44LABREC
  • MEMBER
So if I'm understanding you correctly, you suggest changing the second O2 Senser to OEM if it is not one, then clean the connections, clear code and see what happens? The car does run smooth and there are no driveability issues.
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Saturday, May 16th, 2009 AT 11:50 AM
Tiny
JACK42
  • EXPERT
Yes, that is a good place to start. You can also have the car put on a gas analyzer to see if the cat converter is actually working properly too.
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Saturday, May 16th, 2009 AT 2:41 PM

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