PLEASE HELP URGENT!!!

[Mike08Sierra]

OK, so I'm trying to fix my dads truck so it can pass emissions. He has a 2008 GMC Sierra 4.8 1500...

 

We bought a scanner tool to make things easier. But it's throwing out codes like candy on Halloween.. at the present time I have replaced the EVAP canister, I have replaced a bank 2 sensor 1 o2 sensor. I have replaced the whole down pipe with new Walker catalytic converters, I have cleaned the throttle body and MAF sensor..

 

Now after I installed the new Y pipe with converters it threw these codes at me:

 

P0138

P2273

P2270

P2271

 

Can anyone help me please, I have the end of next week to solve this nightmare.... please note: I have only replaced bank 2 sensor 1....

[txab]

2 hours ago, Mike08Sierra said:

OK, so I'm trying to fix my dads truck so it can pass emissions. He has a 2008 GMC Sierra 4.8 1500...

 

We bought a scanner tool to make things easier. But it's throwing out codes like candy on Halloween.. at the present time I have replaced the EVAP canister, I have replaced a bank 2 sensor 1 o2 sensor. I have replaced the whole down pipe with new Walker catalytic converters, I have cleaned the throttle body and MAF sensor..

 

Now after I installed the new Y pipe with converters it threw these codes at me:

 

P0138 

P2273 

P2270 

P2271 

 

Can anyone help me please, I have the end of next week to solve this nightmare.... please note: I have only replaced bank 2 sensor 1....

P0138  high voltage. bank 1, sensor 2

P2273  stuck rich. bank 2, sensor 2

P2270  stuck lean. bank 1, sensor 2

P2271  stuck rich. bank 1, sensor 2

What were original codes? Have you checked all wiring and voltages at O2 sensors? Notice the pattern above? All downstream sensor codes. Did you transfer the old sensors to the new y-pipe?

 

 

 

[carnau]

4 hours ago, Mike08Sierra said:

OK, so I'm trying to fix my dads truck so it can pass emissions. He has a 2008 GMC Sierra 4.8 1500...

 

We bought a scanner tool to make things easier. But it's throwing out codes like candy on Halloween.. at the present time I have replaced the EVAP canister, I have replaced a bank 2 sensor 1 o2 sensor. I have replaced the whole down pipe with new Walker catalytic converters, I have cleaned the throttle body and MAF sensor..

 

Now after I installed the new Y pipe with converters it threw these codes at me:

 

P0138

P2273

P2270

P2271

 

Can anyone help me please, I have the end of next week to solve this nightmare.... please note: I have only replaced bank 2 sensor 1....

Ok the first thing you need to do is check the oxygen sensor fuses. A lot of times a shorted O2 sensor can cause the fuse to blow and set multiple codes. Let me know what you find and if we need to we can get further into the schematic. Fuse 18 and 8 in your under hood fuse block.

 

I always say this and I believe it 100% if the fuses are good check it with a fuse buddy and make sure the fuse is passing the right voltage. 

Fuse buddy. http://amzn.to/2iEmCq4

 

 

 

 

[Mike08Sierra]

Txtab:

I swapped all old o2 sensors to the new pipe. I know it's not the best thing to do, but I don't want my dad to spend tons of money. I eventually replaced bank 2 sensor 1 and I replaced bank 1 sensor 2 which had the high voltage.

 

I cleared the codes, drove the truck for 25min no CEL popped up. So we'll see I guess.

 

Carnau:

 

I will be heading back over to his house soon, I will check those fuses and let you know anything I find.

[Mike08Sierra]

OK here's an update... I have replaced the catalytic converters, all 4 o2 sensors.. the evap solenoid, cleaned the throttle body, cleaned maf sensor... I replaced the intake plenum gaskets and the oil valley gasket while I was there...

 

It keeps giving me the stupid P0420 code.. now I am lost. Also the evap system will not ready, and I've read it's a PITA to get it to ready up.

 

Any help will be greatly appreciated.

[Colossus]

how soon after clearing the codes do they re-appear?  Also- is the P0420 the only code you are dealing with now?  if so- and if you have not done so already, give the wiring of the sensor a really good look over.  tracing it back as far as you can.  Any chance of an exhaust leak?  You've obviously thrown a lot of parts and $$$ at this thing but I'm still going to ask the obvious questions.