2001 Dodge Caravan EVAP System Issue: P0455 Code Reappears After Cap and Hose Repairs
Hi everyone, About a month ago, I took my 2001 Dodge Caravan for an emission test — it passed. The day after, the "check engine" light came on. I visited Auto Zone to scan the OBD and found code P0455, indicating a large or small evaporative system leak. The technician recommended replacing the gas cap, which I did. Four days later, the check engine light returned. I took it back again — same diagnosis: new gas cap installed. Three days after that, the issue repeated. I then inspected all EVAP hoses, canister connections, and service port under the van. I replaced the purge valve, and for five days everything seemed fine until the light came on once more. At this point, I’m frustrated — the problem keeps recurring. The odd part is a sound that occasionally occurs during driving: it sounds like a trumpet or loud hiss, similar to what happens during a soccer game. I suspect pressure builds somewhere in the system and then releases suddenly. Using my own OBD2 scanner, I ran the I/M test and saw "NO" readings for catalyst, EVAP, O2, and EGR systems. This seems unlikely — I don’t believe multiple systems are failing simultaneously. Instead, I suspect one issue is triggering others. What could be causing this? What should my next diagnostic steps be? Thanks for any insights or suggestions! Vehicle: 2001 Dodge Caravan (3.3L V6 Flex-Fuel) Mileage: ~160,000 miles Maintenance history: O2 sensor and condenser replaced; all standard maintenance performed (oil, brakes), no other repairs.
The 'NO' or 'not ready' readings you're seeing are not indicative of actual system failure — they occur because you've cleared the codes. All non-continuous monitors reset to 'not ready' after a code reset. The trumpet-like sound is unlikely to be caused by the EVAP system itself. What exactly is producing that noise? Where does the purging originate from? That may be the key to diagnosing the root cause.