P0456 Fault in 2002 Dodge Grand Caravan Sport (59,000 Miles) - Evap System Diagnosis & Repair Guide

It's unlikely the Evap system is still under federal extended warranty. Start by checking the gas cap—it’s a common cause, though often the issue lies with a cracked vacuum hose. Be sure to refer to the vehicle’s vacuum hose diagram under the hood for proper inspection points.

I was right—my 2002 Grand Caravan has expired federal extended warranty on its Evap system. I replaced the gas cap as a precaution, but upon inspecting the vehicle under the hood, I found that the vacuum hose connecting the front and rear vapor canisters is cracked on both sides. All other hoses appeared intact. The issue will now require replacement with a new molded hose at the dealer. We’ve taken great care of this van since new, so it’s surprising how much deterioration has occurred—possibly due to gas vapors drying out the rubber over time. I’ll update you once the repair is complete and hope no further codes appear.

The Evap hoses typically cost under $20 each, and I replace about two per week. There seems to be a growing trend where these hoses degrade prematurely—likely due to increased exposure to vapors and chemicals from the emissions system over time, which break down rubber components.

I just purchased the replacement hose today (slightly molded, approximately 5/8 inch in diameter and 8 inches long) for $4.50 including tax in the U.S. I’m optimistic this will resolve the issue. I never dismiss these small problems—they actually keep me sharp for more complex repairs down the line. Thanks for the help!

Hi there—I have a question about P0456 and related codes (P0442, P0455, P0456). My mom has a 2002 Grand Caravan with these issues. I plan to inspect the hoses for her soon. Could anyone clarify where the vapor canisters are located on this model? Also, is there a way to view these codes directly on the odometer, or do I need a dedicated OBD-II scanner?

You’ll need an OBD-II code reader. The location is typically near the middle of the vehicle, on the driver’s side, just behind the engine cradle assembly under the floorboard.

I have a 2005 Grand Caravan with P0456. I’ve already checked the visual condition of the gas cap and tightened it—though it appears fine. Is it still possible for the gas cap to be faulty even if it looks intact? Can such issues be visually detected, or is there another way to tell?

Yes, it’s very possible. A gas cap may fail to seal properly—even if it appears undamaged. Since the sealing function isn’t visible during inspection, you can only confirm its effectiveness through the vehicle's ECM after installation. If the cap fails to maintain a proper seal, the P0456 code will be triggered.

Be cautious when using aftermarket gas caps—many do not seal properly or lack the correct internal valve design needed to keep the charcoal canister off during operation.