I had a Evap code on my Dodge 1500 truck. Turned out to be a cracked vac hose. So far, no codes ever on 2002 Cavalier, 2004 Impala, 2008 Malibu and Colorado. I like the OBD-2 system as it tells you more specifically what is wrong. I won't jump into the import vs. domestic debate, but u can see from the cars I own how I stand there.