First post - need help! - 6 codes will NOT go away

[vanderandrew]

So my 2000 Silverado (5.3) has had the check engine light on for nearly a year now. Oh yea - but the truck stil runs great. I have had it in to a reputable GM dealer twice, my local small town mechanic 3 times and every time the scanner if plugged in, it pukes out 6 codes. If the codes are reset, they come back within a couple days.

1) P0155 2) P0420 3) P0430 4) P0446 5) P0420 P 6) P0430 P

 

Sorry for the lack of detail there but those number were just taken with a buddy's cheap scanner that I am borrowing. We have replaced nearly all of the o2 sensors. Wiring should be good. Unsure of the cats.

 

The mechanics are out of ideas. The last time I brought it in (just a couple weeks ago) they said the only other thing we can do is start replacing everything for the different six code (cats, o2 sensors, evap stuff, etc...) to the tune of nearly a $2000 bill. I am not very excited about spending $2000 while they are grasping at straws.

 

Not sure where to go next. Is there anything that could be causing all of those codes at the same time??

[gmtech4]

give me a minute

 

p0155- o2 sensor performance bank 2 ,sensor 1,,,probably no good ,get it diagnosed

 

p0420\

p0430-cat converter low effecicy

 

p0446-evap vent system performance,,,,,there is a bulletin for this code and calls for a reprogram for the pcm

 

you repeated a couple of codes for some reason newbe lol

 

here is my thoughts if i may

 

12 yr old truck .......if it runs fine and doesnt get chitty milage ...drive the truck ,i would however get the evap vent solinoid and canister replaced and the filter relocated to under the hood ....

 

you dont want to ruin a fuel tank by it caving in and

 

get the o2 code looked at but you mentioned you replaced some ???

 

 

anyway ,it adds up to a bunch of money ,,..

 

i didnt help much except tell what the codes meant ,,,,

 

dont spend to much on the truck

[vanderandrew]

You're right. Very much a noob. I put all 6 codes down because that is what the scanner said. Not sure why it repeated 2 codes with a P on the end. What is the best way to test the wiring for the o2 sensors?