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#4811479 - 07/11/18 03:35 PM The dread P420 code
Oldtom Offline

Registered: 07/05/14
Posts: 334
Loc: Cecil County Maryland
I have a 1998 Toyota Tacoma with 2.4 liter 4 and 5 speed. Got a check engine light and Advance Auto said it was a P420 code. I have to get this truck through smog one last time before I register it as historic. I understand there are off road only O2 simulators that send a "clean" signal. Would this work as a temporary fix just to get thru smog one last time? Underdog Racing makes one.

#4811483 - 07/11/18 03:42 PM Re: The dread P420 code [Re: Oldtom]
slacktide_bitog Offline

Registered: 03/20/08
Posts: 6342
Loc: USA
Replace the cat and the oxygen sensors smile

Rock Auto has a Walker cat for about $100

#4811486 - 07/11/18 03:45 PM Re: The dread P420 code [Re: Oldtom]
MCompact Offline

Registered: 07/21/02
Posts: 4188
Loc: KY
Spark plug anti-foulers will do the same thing.
2014 M235i
1999 Wrangler Sahara
1995 318ti Club Sport

2016 i3 REX
2009 Cooper Clubman

2009 328i

Buy what makes you smile...

#4811490 - 07/11/18 03:51 PM Re: The dread P420 code [Re: slacktide_bitog]
Wolf359 Online   content

Registered: 04/27/12
Posts: 4874
Loc: MA
Originally Posted By: slacktide_bitog
Replace the cat and the oxygen sensors smile

Rock Auto has a Walker cat for about $100

Ditto above. Some of us like to breathe too. This is like asking how to cheat on your taxes.

#4811496 - 07/11/18 03:54 PM Re: The dread P420 code [Re: Oldtom]
SHOZ Offline

Registered: 06/28/03
Posts: 5801
Loc: Illinois
I got a new post cat sensor and a extended for my Accent. Code has not come back in 3 months.
2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual

#4811501 - 07/11/18 03:57 PM Re: The dread P420 code [Re: Oldtom]
dogememe Offline

Registered: 04/15/17
Posts: 692
All new Denso (NOT Bosch junk) O2 sensors and reset the codes and take a few long highway trips and then take it for smog. If that doesn't work you need a new cat.

Edited by dogememe (07/11/18 03:57 PM)
1997 Suburban 5.7 ~214K Miles, VWB 5W-30, VO-55, Personal.
2007 Crown Vic P71 4.6 ~124K Miles, VAS 5W-30, RP 20-820, Personal.
2010 Escape 2.5 ~73K Miles, VAS 5W-30, Wix 51348, Rented on Turo.

#4811502 - 07/11/18 03:58 PM Re: The dread P420 code [Re: Oldtom]
JamesBond Offline

Registered: 12/13/06
Posts: 859
Loc: midwest
I get that code on my Honda every so often, usually after a long highway drive or after disconnecting the battery. I just reset it with the Torque app and I'm usually good for months. I've been doing this for years. I just make sure that there are no lights or codes, and it's run a drive cycle before I take it in for the stupid state inspection.

#4811508 - 07/11/18 04:03 PM Re: The dread P420 code [Re: Oldtom]
Nick1994 Online   content

Registered: 02/19/13
Posts: 10277
Loc: Phoenix, AZ
Just get an aftermarket cat and have an exhaust shop on the bad side of town weld it on. I did that last year for my Jeep, was $40 to have it welded on.
2015 Hyundai Sonata 2.4L 80k Mobil 1 AFE 0w30 & OEM
2000 Toyota Camry 2.2L 228k Mobil 1 AFE 0w30 & Wix
1996 Jeep Cherokee 4.0L 146k Mobil 1 HM 10w40 & Fram Ultra

#4811510 - 07/11/18 04:05 PM Re: The dread P420 code [Re: Oldtom]
mehullica Offline

Registered: 08/19/09
Posts: 563
Loc: Modesto,CA
To answer your question & not get into an emissions morality thread, O2 simulators will work to pass smog if they use the correct capacitors inside. I know several people who use them in California with no issues.

#4811519 - 07/11/18 04:12 PM Re: The dread P420 code [Re: MCompact]
rooflessVW Offline

Registered: 12/24/11
Posts: 4301
Loc: North Carolina
Originally Posted By: MCompact
Spark plug anti-foulers will do the same thing.

Exactly. Gut the cat and space the O2.
"Zed's dead baby, Zed's dead."

#4811520 - 07/11/18 04:15 PM Re: The dread P420 code [Re: Oldtom]
Audios Offline

Registered: 11/19/11
Posts: 942
Loc: Lyndhurst NJ
Ive had luck with running a good injection cleaner, premium fuel, resetting everyhting and going up and down the highway in 4th gear, keeps the revs high and the cats hotter, and going right to inspection after about 50-55 miles. I believe they make a product called cat-a-clean but i cant comment on how it works.
2002 VW Golf TDI-Mobil 1 5/40 TDT
2005 BMW M3 BMW Twin Power 10/60
1998 BMW M3/4/5 Fuchs 5/40
2007 Mercedes GL320 CDI Fuchs 5/40 GT Pro XTL

#4811565 - 07/11/18 05:01 PM Re: The dread P420 code [Re: MCompact]
eljefino Offline

Registered: 06/15/03
Posts: 32763
Loc: ME
Originally Posted By: MCompact
Spark plug anti-foulers will do the same thing.


#4811573 - 07/11/18 05:14 PM Re: The dread P420 code [Re: Oldtom]
Chris142 Online   content

Registered: 06/05/03
Posts: 16947
Loc: Deplorable in apple valley, ca
Make sure that you don't have any vacuum leaks. Those can cause the 420 code too.
02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40

#4811627 - 07/11/18 06:18 PM Re: The dread P420 code [Re: Oldtom]
LeakySeals Offline

Registered: 02/18/11
Posts: 6618
Loc: Hudson, NH
There is a price to pay for oil consumption.
06 Escalade 6.0L AWD 160k. M1 5w30 Fram TG
03 Maxima 3.5L 152k ST HM 10w30

#4811671 - 07/11/18 07:06 PM Re: The dread P420 code [Re: Oldtom]
FermeLaPorte Online   content

Registered: 07/25/17
Posts: 500
Loc: Texas (south)
Time to move to another state
Always Mobil 1
2014 1.6L Nissan Versa Sedan, 5 spd, 5k OCI.
2011 3.5L Chevrolet Impala, Automatic, 5k OCI.

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