Dodge Caravan 2003 Check Engine Light with P1684, P0442, P0455, and P0456 - Is It Just a Gas Cap Issue?

I'm experiencing the same issue with my 2002 Dodge Town & Country 3.8L. I'd love to know if replacing the gas cap resolved your problem. Interestingly, about two weeks before the check engine light came on, I was filling up at a gas station. While the fuel nozzle was in place, I accidentally pressed my keyfob to open the automatic left rear sliding door. It unlatched slightly (only an inch) and then automatically relocked—thankfully, this safety feature prevented any contact with the nozzle. I drove about 5 miles home that day without noticing the check engine light (though I can't rule out it turning on at that moment due to distractions). The next day, when I started driving again, the check engine light appeared immediately. AutoZone scanned it and reported P0456. I checked the gas cap tightness, disconnected the battery to clear codes, and the light returned within a few days. Later, using the 'key on-off-on-off-on' method, my scanner showed P1684, P0442, P0442, and P0455. It feels like a strange coincidence that the check engine light activated just 5 miles after attempting to open the rear door with the fuel nozzle in place—could this be related? I'm not sure if there's a connection or if it's just a random timing issue.

I took my vehicle to a repair shop, and so far they haven't found any issues with the hoses. They mentioned that the new gas cap wasn’t tightened properly. So, the diagnosis is still uncertain. If it's not the cap, I'm being told there might be a vacuum seal issue somewhere in the system. I haven't searched deeply yet for forums discussing this specific problem—any advice would be appreciated. I need to fix this soon to pass emissions testing.

I returned from the shop and the check engine light is now off. I'm hopeful it stays that way, though I suspect it might come back. The mechanic only did a visual inspection of the hoses—no smoke test was performed. They said they’ll do one if the light returns. There’s a helpful thread on this page discussing these exact codes—I found it very useful.

jcole2424—just checking in, but my check engine light came back on recently. So I don’t think the gas cap was the real issue. Thought I had resolved it, but now it's back. Ugh.

Sorry to hear that. Was hoping the silence in this thread meant you'd found a solution. Well, thankfully I have one year before my vehicle needs DEQ emissions testing. Thanks for sharing your update—your experience is helpful and keeps others informed!

Great to know I'm not alone! I brought the van back from the shop again after the check engine light returned. They replaced an evaporative system hose following a smoke test. The exact location isn’t specified, but the service record notes it's an evap hose. The part cost $20. Total repair: $123 (parts + labor + smoke test). I hope this fixes it. The codes that reappeared were P1684 and P0455.

I found a helpful video online that might assist others in diagnosing evap system issues. It's worth watching, especially if you're getting similar codes. Link: http://www.youtube.com/watch?v=CSn0ljUS...data_player The creator answers questions in the comments section—very informative for DIYers and mechanics alike.

Thanks for sharing that—it's really helpful!

My 2001 Dodge Caravan is now running with a misfire and hesitation, especially when I press the accelerator. I replaced an O2 sensor about three months ago. Now it hesitates until I floor the gas pedal. I discovered a broken clamp on the evaporative valve located under the vehicle near the driver’s seat—this may have contributed slightly, but the engine still misfires. The check engine light shows P0442, P0171, and P0455. I believe the gas cap is dry or rusted and needs replacement. I’ll update if it improves. Next step: fuel filter, then evap valve inspection.