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My 2004 K1500 4.8 4x4 won't pass inspection, codes 420, replaced cat bank 1, code 455 now? Just did a tune up, plugs, wires, tranny,etc.

My 2004 K1500 4.8 4x4 won't pass inspection, codes 420, replaced cat bank 1, code 455 now? I had GM dealership do service bulletin on heater blower motor relay and now "service air bag" light is on as well. Just did a tune up, plugs, wires, tranny,etc. It helped rough idle a lot but still will stall at strange time. I feel it's partially electrical because of bulletin on instrument panel cluster which I learned about after I don't qualify for free replacement due to mileage,(118000) and age. It displays different issues with no specific pattern except for "replace fuel cap" at approx 4-5 miles of driving from a cold start and after tank gets below 1/2 tank. I can't afford to replace/repair I need to troubleshoot 1st. I've asked many mechanics and none of them have heard of my symptoms. Where can I can a detailed diagram of the vacuum and fuel lines so I can check for leaks?

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P0455 Evaporative Emission Control System -Leak Detected (Large Leak)

Would appear you have perished hose somewhere along the line but where ? you would need to do a complete inspection to find it ,no idea even where to look with vehicle as not many here in spain .Now as for airbag light well this is a different ball game here but a lot of vehicles will show the light if the battery goes flat and they need resetting with the right software so consult a local mechanic on this on but do check the wires under the seat as you would be surprissed how many time i have found empty bottles and junk under the front seats which have dislodged the multiplug connection

Posted on Nov 16, 2013


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Posted on Jan 02, 2017

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SOURCE: Rough idle

Jeep has been having a problem with this. i take it u have a 4.7L or a 3.7L. when the when to fix this problem they should of replaced all the valves (intake and exhaust). theres a tsb on this and the dealer can look it up. even if you paid for the service they will fix it for free cuz it wasn't fixed the first time. take it back to the them and tell the to read the tsb and fix it right.

Posted on May 15, 2008

  • 1 Answer

SOURCE: 95 GMC Jimmy 4.3l W vin rough idle

My problem was solved when I repaired my 4 wd activation dash switch. The switch was contacting on 2WD & 4HI at the same time. The front differential activation is vacuum activated possibly creating a tug of war that didn't actually engage it but drained off vacuum from the engine? A theory at best but stumbbled across it because I knew the switch wasn't working properly I repaired it and low and behold rough idle disappeared and all is good for 3 weeks running.

Posted on Dec 10, 2008

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SOURCE: 1996 s10 2.2 engine starts but idles rough and will not rev up.

Hi! You must be frustrated by now! your code is marking that the O2 sensor is bad in bank 1. Did you replace the O2 sensor that is located  before the catalytic converter?  The S10 has an O2 sensor specially made for that cat. its about 30$ That would explain for your blackened spark plugs; your pc on the car is asking for more fuel. GOOD LUCK!!

Posted on Apr 29, 2009

  • 3600 Answers

SOURCE: PO 420 and PO 455 codes

There are three things that can cause this that is unrelated to the cap, if the valve on the carbon canister is defective it would cause this it would also cause a vacuum leak making the car run lean so check the carbon canister check valve first. Next your EGR valve could be dirty or not functioning, depending on the model and engine size it may have two EGR valves one a mechanical and the other the digital EGR and it to may be dirty, if it's dirty it can be taken apart and cleaned with carburetor cleaner and clean the pintal. And lube the pintal valve. If you’re careful and not tear the gasket you can reuse it. If this does not seam to fix the problem then you have a vacuum leak or the device that pumps pressure into the gas tank may be defective.

Posted on Jun 27, 2009

  • 1 Answer

SOURCE: 1989 Corvette starting and idle problems

my 89 corvette is hard to start when it is cold, and runs very rough for about a minute. replaced the IAC and Maf sensors had the throttle body cleaned, now it idles very high and emits the same problems. i also had the injectors cleaned.

Posted on Sep 19, 2009

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P1884 code 2005suzuki forenza P0420 P0134 P0138

code p 420 refers to cat converter system , bank 1--efficiency below threshold ===causes ---cat converter faulty---wiring --heated oxygen sensor (HO2S), 2 faulty
code p 0134 refers to HO2S 1 bank 1-no activity detected ===causes --wiring open circuit -- heating inoperative --- HO2S
also refers to oxygen sensor ( O2S) 1 bank 1--no activity detected == causes wiring ---O2S
code p 0138 refers to HO2S 2 bank 1--high voltage === causes ---wiring short to positive ---HO2S--- ECM
also refers to O2S 2 bank 1 high voltage === wiring short to positive O2S -- ECM
I do not have a listing for code p 1338 but I suspect that it will refer to the other codes in some way
first fix is to check the cat converter is operational ( not cracked and blocking the exhaust system)
next replace the HO2S sensor ( one before the cat converter ) and then the O2 sensor (the one after the cat converter)
all the codes will relate to problems in that area

Sep 01, 2016 | 2005 Suzuki Forenza

1 Answer

How do I troubleshoot code P0420 and pass emissions

code p 420 refers to catalytic converter system bank 1--efficiency below threshold ===causes--- catalytic converter,--wiring---HO2S 2 sensor
could be a bad HO2S sensor or a failed cat converter
try the sensor first as they are cheaper than a cat

Nov 13, 2015 | 1997 Ford Explorer AWD

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How do I pass vehicle inspection O2 Cat. Evap for a 2004 Chevrolet Cavelier

What was the code given..
02 will mostly sensors..
Cat code 420 will need new cat
And evap codes can b a couple different parts..need exact codes to tell what all is needed for fix

Sep 22, 2014 | 2004 Chevrolet Cavalier

1 Answer

Po 420 ?

code p0420 refers to cat converter system, bank 1 efficiency below threshold===causes --cat converter--wiring HO2S sensor 2

check that the cat converter is ok and replace the sensor. ( it is a HO2S sensor which will be different to a O2 sensor so get the right one )

Sep 12, 2014 | 1998 Chevrolet Astro

1 Answer

2004 nissan xterra run great for 12 miles then misfiring,cnt get over 45 miles an hour. codes p 0733,p0420,p0430,p0328 comes up. new wires,new cap,rotor spark plugs 6 months old timming belt 6 months...

code p0733 refers to gear 3 -incorrect ration===causes---wiring---TR sensor/switch--shift solenoids---transmission mechanical fault
code p0420 refers to catalytic converter system -bank 1---efficiency below threshold===causes--cat converter--wiring--HO2s 2
code po430 refers to cat converter system bank 2--efficiency below threshold===causes--cat converter--wiring ---HO2s 2
code p0328 refers to knock sensor (KS) 1 bank 1--high input===causes--wiring short to positive--KS incorrectly tightened--KS---ECM

basically replace the cat converters as they are blocking the exhaust system and preventing your over 45mph problem
replace the TR sensor/ switch as you have not mentioned a transmission problem
Rectify the problem with the KS as it controls the air/fuel mixture setting which contributes to the car getting hot.

Jan 12, 2014 | Nissan Cars & Trucks

1 Answer

My 2004 K1500 4.8 4x4 won't pass inspection, codes 420, replaced cat bank 1, code 455 now? I had GM dealership do service bulletin on heater blower motor relay and now "service air bag" light is on as...

The only solution I can offer is temporary and could help you at least pass inspection.

  • When you fuel tank is near empty.
  • Fill your car with 3 Gallons regular gasoline and 3 Gallons E85 gasoline.
  • Erase the error codes and drive around for a little while.
  • Then get the inspection done.
  • After you pass inspection fill the car the rest of the way with regular gasoline.

WARNING: This is a last resort effort. Prolonged use of Ethanol (E85) in engines not designed for it can deteriorate rubber fuel lines, oxidize aluminum, and dry gaskets causing them to crack.

Nov 16, 2013 | GMC Sierra Cars & Trucks

1 Answer

Stumble @ 30-40 MPH under ligh acceleration

Problem sometimes is with cheap parts they are bad.Good wires,good plugs,good coils.

May 05, 2013 | 2004 Mitsubishi Endeavor

2 Answers

I just got the code po 420 how do i fix it

Most likely a worn out exhaust converter

PO 420 -- Catalyst System Efficiency Below Threshold (Bank 1)
that is the right or pass side

Rear or Monitor Sensors could be bad ,if converter is less
than ten years old

Aug 06, 2011 | 1996 Ford Explorer

1 Answer

My 2000 Toyo. Tacoma Prerunner TRD V6, truck Failed smog due to the part #3 Functional Computer Tests due to an erased MIL. But had passed the Visual Inspection, and Emissions. So i bought a Code reader...

there are 2 sensors in the system
one is a heated oxygen sensor (HO2S) in the exhaust manifold / pipe before the cat converter that reports the exhaust gas composition to the ECM so that fuel/ air ratios can be adjusted
if that one is faulty it is most likely the reason for running lean or rich
the second sensor is the oxygen sensor (O2) which is after the cat converter and reads the results of the cat converter cleaning the exhaust
you may have to replace both the sensors to get a clearance or replace the cat converter as well as the HO2S unit

Jun 02, 2017 | 2000 Toyota Tacoma PreRunner

2 Answers

P0133, P0420 and P0430 i went to MCV for inspection and they rejected the car. gave me the above codes. when i went to authorized mechanic, he told me that both the catalyic converters are bad and cost...

code p 0133 refers to heated oxygen sensor (HO2S) 1 bank 1---slow response ===causes ---heating inoperative --- wiring ---HO2S
also refers to oxygen sensor (O2S) 1 bank 1--slow response ===causes ---wiring ---O2S
also refers toHO2S 1 bank 1--no signal====causes wiring ---HO2S
the HO2S is the sensor in the exhaust manifold before the cat converter and reads the exhaust gas composition to report to the ECM to adjust air fuel mixture
For this code the HO2S needs replacing
the reference to an O2 S is the sensor after the cat converter and reports on the cat performance
code p0420 refers to catalytic converter bank 1-- efficiency below threshold ==== causes cat converter ---wiring ---HO2S
code p 0430 refers to the same as p 0420 but cat converter bank 2 causes the same including the HO2S
I would first get both HO2S sensors ( bank 1 and bank 2) replaced then have the fault codes read
if the cat converters are sill showing as the 420-430 codes then muffler shops have cheaper cats that what you were quoted

Dec 16, 2017 | 2004 Suzuki Verona

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