Question, I have a work truck it's an 2005 2500 HD 6.6 Duramax. My boss has an 2003 Duramax with a straight thru exhaust system and it doesn't trip a code without the CAT. Now I have heard that the LLY 2005 will trip if you remove the cat, is this true?

Derek

IF you have the FE9 emissions, you should not throw a code. I had an 2005 and removed cat and unplugged the EGR valve and never threw a code.
Check your glove box tag for that code. If you have that code, you should be good to go

Question, I have a work truck it's an 2005 2500 HD 6.6 Duramax. My boss has an 2003 Duramax with a straight thru exhaust system and it doesn't trip a code without the CAT. Now I have heard that the LLY 2005 will trip if you remove the cat, is this true?

Derek

GM installed Catalytic Converters on 2004.5 and after year models. The 2003 6.6 Duramax never had a catalytic converter on it. That is why your boss's truck never threw a code.

I have a 2005 LLY. I deleted my catalytic converter last November. I replaced the stock exhaust with a Magnaflow 4 inch turbo back exhaust. I see two codes. They are the P401 & P404 EGR codes. These are soft codes that I can delete with my HyperPac Computer. These codes do not cause the "Check Engine Light" (CEL) to come on. If your truck has California Emissions System, you will probably see a CEL.

I got rid of my cat and no codes,one big problem though, thanks to the environmentalist they are doing emissions on diesels this yr:mad:

I'm just hearing that removing that cat helps with more power and cooler egt's. It's a work truck so I can start playing with programers and stuff, hell I have an 08 on order right now. I heard it's impossible with all the sensors on the 08's to mess with anything.

I check my 05 and it has the code in the glove box. 10th row 2nd down. That means is should be good to go to say bye bye to the cat?

When my cat ran away, I didn't get any codes (NY Emissions -:t ). When I blocked my EGR, I got codes. I think it's been said that the stock muffler (Assuming yours is still stock) has enough back pressure to keep the EGR happy.

well my 10th row second down is showing FT3. So I guess if I take off the cat it will trip codes...damn

I got rid of my cat and no codes,one big problem though, thanks to the environmentalist they are doing emissions on diesels this yr:mad:

No I am not paying for Emission tests for my diesel this year.

PERIOD! Pa sucks. Oh yeah I am in this dumb state too. :knight:

I check my 05 and it has the code in the glove box. 10th row 2nd down. That means is should be good to go to say bye bye to the cat?
What does this mean. :confused:

I have an 03' and have the EGR and Cat from factory. I have the YF5 and Nc1. (Both California Emissions Codes). Surely someone didn't put it on there? Anyway, are you saying that if I remove the cat, that I will throw a code?

well my 10th row second down is showing FT3. So I guess if I take off the cat it will trip codes...damn

FT3 is the code for the right side torsion bar. All the codes are listed in alphabetical order. If you see FE9, then your truck is certified for federal emissions. You can't look for it in the same position as a different truck since you don't know if you have the same options. Just check here (www.rpocodes.com) for a complete list of codes and their meanings.

What about your warranty . Will Removing the Cat Viod the warranty ?

cool I'll re-check the codes later. I went to the dealer and the mechanic said it will definitly throw codes. Said to leave the CAT on and get a programmer. The cheapest and safest investment.

Just looked Mine is YF5 (calif. Emissions)