2000 Grand Prix GTP SES code P0442

My 2000 Grand Prix GTP set the SES code of P0442 "small emissions leak". Is this something that can be traced and fixed by a person with average mechanical ability? What is the most common cause of this code? I had Advance Auto clear the code and have done a prelimanary check to make sure all the lines were connected and they were in good condition. Also, made sure the gas cap was tight.

P0442 is probably the worse evaporative emissions fault to have. Could be as simple as the gas cap but in most cases not. See tech link below:

http://www.automotiveforums.com/vbulletin/showthread.php?t=622473

Welcome to AF.

What a mess, it would figure that I would get one that is a PITA to deal with. :banghead: Has anybody successfully fixed one of these themselves without a shop helping them? Anybody know the most common cause. A .020-.080 leak is a really small hole in a big system. Any idea on how much a shop would charge to do the smoke test?

What a mess, it would figure that I would get one that is a PITA to deal with. :banghead: Has anybody successfully fixed one of these themselves without a shop helping them? Anybody know the most common cause. A .020-.080 leak is a really small hole in a big system. Any idea on how much a shop would charge to do the smoke test?

Costs for evaporative emissions controls troubleshooting varies. The dealer has the best diagnostics tools using a Tech II. You could check all vacuum lines running from the fuel pump pod to include tank seal to the filler neck and charcoal cannister. From the cannister and vent solenoid the lines run to the purge solenoid at the engine area. Also, make sure vacuum is good coming from the throttle body to the purge solenoid. Other possibility is a defective fuel tank pressure sensor giving erroneous results to the PCM for the small leak down test.

Ok, with the code reset and the gas cap checked for being tight, I have driven the car all weekend and it has not reset the SES light. Any idea of how long it would take to set the SES light again if there truely was a slow leak?

The pcm tests the system only under certain conditions, between 1/4 to 3/4 tank is one ,cafter the code is cleared it requires the normal drive cycle to reset the monitors, a scan will tell you if the evap monitors are on line.