So I can't seem to get my truck to pass emissions due to the fact the catalyst and evap systems come up as not ready.

My truck is a 2004 that originally came with a 4.8L but now has a 6.0L. I also have aftermarket cats which I put on over a year ago. I haven't had any DTC's since I changend the cats so I don't think they are causing any problems.

I have completed the GM drive cycle many times as per the recommendation but I still won't pass.

Any suggestions would be greatly appreciated.

 

Set the catalyst and evaporative purge canister DTCs set to not reported. You'll need tuning software or will need to find someone who can reflash your truck.

 

I tune with CMR so I have access to those parameters. My question is what number do I put in nest to the OBD II tests that I need to modify?

 

I am not sure what you are asking (numbers to put in next to OBDII tests?), but if you'll set the processing enablers for DTC P0420, P0430, P0440, P0442, P0443, P0446, P0449, and P1441 to "not reported" or "X", the EPA tests should all report as passed/completed.

 

You can put 0, 1, 2, or 3 next to the OBD II code that you are modifying. I just don't know what each number means? I am using CMR by the way.

I found every code but P0440 and P1441.

 

Sorry, I thought CMR might have been a shop or something you had access to. My mistake.

There are four conditions: not reported, non-emissions, emissions-related one trip failure, and emissions-related two trip failure. I would guess that the numbers 0-3 correspond in that order, or in the opposite order.

What do you have for those codes currently? If you can't tell, try all zeroes or all threes. If you have the ability to check the readiness tests before going in for inspection, the guess-and-check method isn't so bad.

 

In HP tuners it is in the opposite order as you described so I think it's the same in CMR (Chipmaster Revolution). BTW CMR is the tuning program that works with the diablosport hand held tuner.

I will put a 3 in the codes you mentioned so that the code is not reported. All of those codes currently have a 1 so I assume it's a one trip faliure.

 

0=MIL ON after first key on failure 1=MIL ON after second key on failure 2=NO MIL Light 3=No Error Reported

This is what I understand the DTC functions to be, but I always just change the stock value to a 3 to disable the function.

Ryan

 

you will want 3 for EVERYTHING. MIL status, DTC... make sure you get EVERYTHING. I ran into this and had to find those stragglers that my eyes didn't catch the first time

 

I entered 3 in for all codes pertaining to the rear o2 sensors and evap. Loaded the tune and as soon as I started the scanner the cataylist was complete! Evap still wasn't complete but I can have 1 incomplete test and still pass. I did just change the fuel tank pressure high and low voltage codes to 3 in hopes that the evap will complete but haven't tried it yet.

Thanks again to everyone that helped!

 

Even though it doesn't matter, there are probably some codes for the evap that are in your OS but aren't in mine. If you can look through the list, I'm sure you'll find them.

 

Well I inserted a 3 into all of the codes pertaining to the EVAP and the rear O2 sensors and it passed emmissions!

Thanks again to everyone that helped. This is a big weight off my shoulders.