Code P0420

WROJAS0919

MEMBER
2003 MITSUBISHI LANCER
124,600 MILES

Need help please. Don't know if it's the downstream sensor ar catalystic. Thanks

Friday, March 4th, 2016 AT 10:39 AM

8 Replies

DRCRANKNWRENCH

MECHANIC
3,380 POSTS

I looked up the code in our online guide. Attached are the notes from said code. Let me know if you need more information. One of the sensors probably needs replacement.

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Friday, March 4th, 2016 AT 11:18 AM

WRENCHTECH

MECHANIC
20,757 POSTS

I've seen this code a lot and there are just 2 things that i've ever seen set it

Bad converter 95%
Exhaust leak ahead of the converter 5%

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Friday, March 4th, 2016 AT 3:21 PM

WROJAS0919

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Thanks for the reply!
How would I be able to tell if its a leak?

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Friday, March 4th, 2016 AT 3:35 PM

WRENCHTECH

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You put it up on a lift with the engine running and carefully feel all around until you feel the air puffing.

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Friday, March 4th, 2016 AT 3:58 PM

WROJAS0919

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Its not a leak, the car has two catalystics how can I tell witch one it is? And it only has two sensor :/.

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Friday, July 29th, 2016 AT 3:45 PM

WRENCHTECH

MECHANIC
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P0420 applies to bank one if you have a V6. That is the only bank if you have a 4 cylinder. It will be the converter just ahead of the downstream sensor. The sensor could be right in the converter itself.

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Friday, July 29th, 2016 AT 4:03 PM

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