Po420 Is Back!!!!!

nnunez · 01-28-2008, 10:54 AM

Its like Poltergeist. ITS BACK!!!!!

I have replaced the Cat, the plugs, wires, cap & rotor, fuel filter, brakes, calipers, etc, etc within the last 6 months. I could not find any vaccum leaks. Engine does not seem to misfire, it does not bur oil (not much anyway)........

Any suggestions?

junior3382 · 01-28-2008, 11:01 AM

hey, perhaps it is a ghost code.... they say those do not exist, but my truck has one every so often too. I think technology is messing with us, and sending us false signals. The revolution is near. LOL!!

1979_4x4_Plow · 01-28-2008, 12:31 PM

i have owned vehicles where the engine light would come on as a reminder to get it in for its service. every 60,000 miles the light would kick on and need to be reset as a way to say, take me to the mechanic and have me checked out.

junior3382 · 01-28-2008, 12:37 PM

yea, but the easiest way to do that is disconnect the battery for over 60 seconds then drive it to reset the monitors, and he would had to do that to replace the cap and rotor, unless he walks on the edge.... LOL. at least I would have disconnected it. If so, and the code came back, that is probably not the issue. The computer sees soemthing, but like a child, it cannot describe it well enough to resolve it.... hmmmm, I hate technology!

jimbo543 · 01-28-2008, 02:17 PM

what year,model,engine and i'll help diag it

nnunez · 01-29-2008, 02:22 PM

it is a Silverado 1996 5.0L.
i went to the Autozone yesterday and thats the code it read.
today i went to the mechanic and he said no code was read.
the engine light is still burning.

scrappiedew1 · 01-29-2008, 05:48 PM

I had this code on my jeep grancherokee same meaning different car, what i had to do was replace both 02 sensors the before and the one in the cat the code is a strange one but it has been almost a year it has not come back my buddy that is dodge mechanic told me that keep a eye on your milage if realy starts to drop then u have a problem hope this helps

crabtruck · 01-29-2008, 11:33 PM

Light is on and "no code was read"? Is this the signal of a failing computer? Have you checked that you're not getting a short between light and computer?

nnunez · 01-30-2008, 10:01 AM

Well, I did notice that the mechanic removed and reinstalled the CPU fuse (cant remember the label exactly) and it worked after that.

Now, the light was on yesterday when I went to the mechanic and on the way home (I drive about 90 miles to and from work daily) and this morning, no light at all.

keithr0005005 · 01-30-2008, 06:30 PM

just ignore it lol

01-28-2008, 10:54 AM	#1
nnunez Senior Member Join Date: Dec 2005 Posts: 307	Po420 Is Back!!!!! Its like Poltergeist. ITS BACK!!!!! I have replaced the Cat, the plugs, wires, cap & rotor, fuel filter, brakes, calipers, etc, etc within the last 6 months. I could not find any vaccum leaks. Engine does not seem to misfire, it does not bur oil (not much anyway)........ Any suggestions?

01-28-2008, 11:01 AM	#2
junior3382 Senior Member Join Date: Mar 2007 Location: Currently, I live in Lancaster county, Pennsylvania. Posts: 3,170	hey, perhaps it is a ghost code.... they say those do not exist, but my truck has one every so often too. I think technology is messing with us, and sending us false signals. The revolution is near. LOL!! __________________ *The Blazer is dead, so I pumped her with lead, laid her to bed, and bought a FORD instead!*

01-28-2008, 12:37 PM	#4
junior3382 Senior Member Join Date: Mar 2007 Location: Currently, I live in Lancaster county, Pennsylvania. Posts: 3,170	yea, but the easiest way to do that is disconnect the battery for over 60 seconds then drive it to reset the monitors, and he would had to do that to replace the cap and rotor, unless he walks on the edge.... LOL. at least I would have disconnected it. If so, and the code came back, that is probably not the issue. The computer sees soemthing, but like a child, it cannot describe it well enough to resolve it.... hmmmm, I hate technology! __________________ *The Blazer is dead, so I pumped her with lead, laid her to bed, and bought a FORD instead!*

01-29-2008, 05:48 PM	#7
scrappiedew1 Senior Member Join Date: Jan 2008 Posts: 103	p0420 I had this code on my jeep grancherokee same meaning different car, what i had to do was replace both 02 sensors the before and the one in the cat the code is a strange one but it has been almost a year it has not come back my buddy that is dodge mechanic told me that keep a eye on your milage if realy starts to drop then u have a problem hope this helps

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01-28-2008, 12:31 PM	#3
1979_4x4_Plow Senior Member Join Date: Dec 2007 Posts: 98	i have owned vehicles where the engine light would come on as a reminder to get it in for its service. every 60,000 miles the light would kick on and need to be reset as a way to say, take me to the mechanic and have me checked out.

01-28-2008, 02:17 PM	#5
jimbo543 Senior Member Join Date: Sep 2007 Location: MN Posts: 208	what year,model,engine and i'll help diag it

01-29-2008, 02:22 PM	#6
nnunez Senior Member Join Date: Dec 2005 Posts: 307	it is a Silverado 1996 5.0L. i went to the Autozone yesterday and thats the code it read. today i went to the mechanic and he said no code was read. the engine light is still burning.

01-29-2008, 11:33 PM	#8
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,135	Light is on and "no code was read"? Is this the signal of a failing computer? Have you checked that you're not getting a short between light and computer?

01-30-2008, 10:01 AM	#9
nnunez Senior Member Join Date: Dec 2005 Posts: 307	Well, I did notice that the mechanic removed and reinstalled the CPU fuse (cant remember the label exactly) and it worked after that. Now, the light was on yesterday when I went to the mechanic and on the way home (I drive about 90 miles to and from work daily) and this morning, no light at all.

01-30-2008, 06:30 PM	#10
keithr0005005 Senior Member Join Date: Jan 2008 Posts: 156	just ignore it lol

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