2007 Sierra OBDC II codes unknown

[thx1138v2]

I'm trying to get my 2007 Sierra 4.3L truck inspected but it's not passing. The "CHECK ENGINE LIGHT is not lit.  The gas tank indicator shows between 1/4 and 3/4 full.

 

It was throwing a "P0455" code and that was repaired by replacing the carbon canister.  Now it's not showing any codes but the text says "FAILED". In another screen it has items "CATALYST MON" that shows "INC". It also has a line item for "EVAP SYSTEM MON" that shows "INC". I'm guessing that means "INCOMPLETE" initialization but I'm just guessing. I don't have a manual for this instrument.

 

I took the truck to a GMC/Chevy dealership and their monitors wouldn't show anything at all.

 

I've done 2 drive cycles per instructions from the web.

 

Any suggestions are welcome.

[asilverblazer]

You will probably need more drive cycles for the system to run its own tests. I don't know how many or how far they may be though. 

 

Resetting the computer or clearing codes may restart the drive cycle counter too, so beware of being tempted to do that to speed up the process.

[davester]

charm.li (website) should have driving instructions for each of the monitors, so increase the likelyhood that the conditions are right for the monitor to run it's test procedure.