Help P0420!!!!

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Caedmon7777

Member

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2010 Mazdaspeed 3

• Oct 6, 2005

• #1

My '00 DX is throwing the P0420 code on and off interrmittenly for a while I think it's the O2 sensor but the guy at Autozone said that it could be that the first piston might be misfiring. I have roughly 110,000 miles on it and about to change the belts on it. Do you think changing the belts will help or do I need to do the O2 sensor too? Help would be very much appriciated.

 

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Witchdoktor

Banned

Contributor

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99 LX

• Oct 10, 2005

• #2

P0420 http://www.msprotege.com/forum/search.php?searchid=1456819

 

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Shane5425

Contributor

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2011 Mustang GT

• Oct 10, 2005

• #3

k, po420 = What?? cylinder 1 misfire or something/? we need more info..

 

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Killer 8

Member

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2003 Protege DX

• Oct 10, 2005

• #4

have you done anything to the 02 or you could just take it out and look at it cause it might just need to be replaced since you have so many miles on it. Also did they give you a print out on what the code is?

 

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boostisgood

Member

:

1988 FC3S TII

• Oct 10, 2005

• #5

DTC PO420- Catalyst efficiency below threshold.

Possible cause
Cat defective or deteriorated
Exhaust gas leak
Loosness of frt HO2s
Loosness of rear HO2s
HO2s FRT malfunction

This is from Alldata, I cant post the whole page on the code at work. Sorry.

 

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boostisgood

Member

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1988 FC3S TII

• Oct 10, 2005

• #6

BTW, dont listen to the guy at autozone. They dont know s***, thats why they are autozone. If you had a misfire you woulda recieved a misfire code po301 for a #1 cyl miss 302 for #2 303 for #3 304 for #4 or 300 for a random.

 

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Shane5425

Contributor

:

2011 Mustang GT

• Oct 10, 2005

• #7

id say 2nd o2 sensor. seems to be most common

 

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TampaSport20

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2000 Protege DX

• Oct 10, 2005

• #8

99-00 if its federal emissions (not california) only has one cat and one 02 sensor

 

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boostisgood

Member

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1988 FC3S TII

• Oct 10, 2005

• #9

No, anything after 96 has 2 O2 sensors required by FEDERAL Emissions requirements.

 

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Shane5425

Contributor

:

2011 Mustang GT

• Oct 10, 2005

• #10

TampaSport20 said:

99-00 if its federal emissions (not california) only has one cat and one 02 sensor

Click to expand...

we have 2.. trust me

 

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solid_snake

Member

:

2006 Mazda Tribute S-V6

• Oct 10, 2005

• #11

TampaSport20 said:

99-00 if its federal emissions (not california) only has one cat and one 02 sensor

Click to expand...

2 sensors, i had a CEL with like 4 codes, and i replaced 2 HO2S when i had my protege

 

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TampaSport20

Member

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2000 Protege DX

• Oct 10, 2005

• #12

solid_snake said:

2 sensors, i had a CEL with like 4 codes, and i replaced 2 HO2S when i had my protege

Click to expand...

Didnt you also try to inform me where the EGR valve is on my federal emissions 1.6L , which has no egr system

 

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solid_snake

Member

:

2006 Mazda Tribute S-V6

• Oct 10, 2005

• #13

TampaSport20 said:

Didnt you also try to inform me where the EGR valve is on my federal emissions 1.6L , which has no egr system

Click to expand...

well, maybe i had a non-federal emissions in my car, but the california one, who knows... but it had only one cat (boom07)
sorry for any inconvenience

 

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TampaSport20

Member

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2000 Protege DX

• Oct 10, 2005

• #14

solid_snake said:

well, maybe i had a non-federal emissions in my car, but the california one, who knows.
sorry for any inconvenience

Click to expand...

that means you have 2 cats and 2 sensors....

no inconvenience...just giving you a hard time...hard to convey in text (thumb)

 

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TampaSport20

Member

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2000 Protege DX

• Oct 10, 2005

• #15

shaneMazda2000P said:

we have 2.. trust me

Click to expand...

lol, I dont trust you anymore with your sideways PRC valve

 

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solid_snake

Member

:

2006 Mazda Tribute S-V6

• Oct 10, 2005

• #16

TampaSport20 said:

that means you have 2 cats and 2 sensors....

no inconvenience...just giving you a hard time...hard to convey in text (thumb)

Click to expand...

well maybe i was just aware of the 1st cat,
anyways, i replaced 2 HO2Ss, and the TPS, and the stupid CEL was still on...
yeah i disconnected the neg battery cable when i replaced them

but the tranny was starting to act up too (O/D light flashing)
oh well, i don't have that care anymore

 

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Shane5425

Contributor

:

2011 Mustang GT

• Oct 10, 2005

• #17

TampaSport20 said:

lol, I dont trust you anymore with your sideways PRC valve

Click to expand...

lol, i had to make room for my begi rrfpr... lol

 

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Caedmon7777

Member

:

2010 Mazdaspeed 3

• Oct 11, 2005

• #18

shaneMazda2000P said:

lol, i had to make room for my begi rrfpr... lol

Click to expand...

Well I think I need to change the Belts. I have been smelling a burning smell by the belts when I rev the engine. I think the belts are worn. I will change the O2 sensor but I think I will change the belts first. thanks for the help guys. By the way, how much does it cost to change the timing belt?