Our 2003 Grand Caravan ES 3.8l (97K) has a check engine light with the following codes:
P1491 - Aux Emissions Control
P0442 - Evap Emission Systems Leak - small
P0445 - Evap Emission Systems Leak - large
Since I normally put gas in it I check the gas cap tight. While under it last oil change the plastic hose clamps on Charcoal Canister were broke, so I replaced them with regular hose clamps. The canister & hoses "looked" okay. The errors have not cleared in 3K miles.
Is there a typical point of failure on this vehicle that generates these codes? Is it good practice to replace the hoses and/or canister at this point? Should I be looking at a different component for these codes?
Thanks,
Ray

 

the 1st code should go away once you find the leak.

I think the easiest way to find Evap leaks is to have the system smoked

unfortunatley this probably doesnt help you much as most shadetrees will not have one of these machines.

hopefully someone else will know more

 

Another place to look is under the air cleaner. There are two hoses leading to and from a solenoid. Check those carefully. I have the P0442 and P0455 codes which smoke testing found to the fuel filler pipe leaking badly.
P1491 is for the radiator cooling system, not emissions related.