I was asked to look at my nephew's 2003 neon, it has the check engine light on and he needs to regiter it this month. There are 7 error codes I found with my OBD II reader. There are actually 4 codes and the other 3 are repeats.
They are;
Code 442 - Evaporative Emmission Control System Leak Detected (small leak)
Code 455 - Evaporative Emmission Control System Leak Detected (gross leak)
Code 456 - Evaporative Emmission Control System Leak Detected (very small leak)
Code 440 - Evaporative Emmission Control System Malfunction
Code 442 -
Code 456 -
Code 440 -

I found out that the gas cap is missing so I sent to him to buy a replacement and will check the rest of the sytem in morning but I thought I would ask you guys if anyone has seen these problems before and what the they did to correct them.

Any tips or suggestions would be appreciated.
Thanks,
Tim

i bet the gas cap solves it.

Agreed

I had codes p0440 and p0441... Evap malfunction, incorrect purge flow.

I went to the dealer, they recommended a new "Proportional Purge Solenoid Valve" (part #04669). Gonna Install it later today, I'll keep you updated.

...and my gas cap was fine.

It might be the gas cap but if it is not
just crawl under the back of the car and inspect all the hoses by the fuel tank my car also had the evap code and it turned out too be a hose