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2001 Grand Caravan P0455 Code: Hissing Noise and Poor Fuel Economy - Possible Causes and Fixes

Model: 2001 Grand Caravan Fault Code: P0455 Posted: 2011-08-13 18:51

I've inspected all visible hoses on my 2001 Grand Caravan and they appear to be in good condition. After following several troubleshooting steps recommended in forum posts, I noticed a distinct hissing sound coming from the top of the gas tank. This has me wondering if this could be related to the P0455 code. I'm hesitant to remove the fuel tank unless absolutely necessary—what specific hoses or components could be causing this hiss? Additionally, I've been experiencing extremely poor fuel economy, around 6–7 MPG, which makes me suspect a leak or system failure. Since I usually handle my own car repairs, any clear guidance on how to diagnose and fix this would be greatly appreciated.

Related fault codes
P0455
Comments (7)
Anonymous 2011-08-14 10:51

Could you please provide more details or suggestions for diagnosing the P0455 code in a 2001 Grand Caravan? I'm trying to avoid costly repairs.

Anonymous 2011-08-14 11:08

Try using a mirror and a flashlight to inspect the area around and on top of the fuel tank—sometimes leaks are visible from there.

Anonymous 2011-08-14 13:30

I used a mirror and light to check, but couldn't see any obvious signs. The hissing seems to originate inside or near the tank. It's difficult to pinpoint exactly where it's coming from. What components are typically located at the top of the fuel tank that could be leaking? I'm also seeing terrible gas mileage—around 6–7 MPG. Since I have limited funds, I want to fix this myself with proper advice. Thanks for your help!

Anonymous 2011-08-14 18:44

You may need to lower the fuel tank to properly inspect it. A common issue is a leaking rollover valve at the top of the tank—this component isn't serviceable without removing the entire tank.

Anonymous 2011-08-16 00:49

Just for reference, I recently encountered P0455 on my own vehicle and discovered that the PVC/emissions hose connecting the valve cover to the intake plenum had cracked due to heat exposure and was completely detached. The hissing noise stopped after replacing it—no check engine light came back. This might be a possibility in your case too, especially if you haven't already checked this hose.

Anonymous 2011-12-30 13:33

I have a 2002 Grand Caravan with the same P0455 code and am experiencing identical symptoms: hissing noise and poor fuel economy. It's reassuring to know this issue appears common in that model year. Did anyone find a reliable fix? I'm due for car maintenance soon, and my wife starts work next week—both cars need to run properly during the weekend. Thanks for any insights!

Anonymous 2012-04-07 10:27

For a 2001 Grand Caravan with P0455, make sure you're not confusing the hissing sound with the electric fuel pump operating at the tank—some users report rust or cracks in the filler neck area just below the cap. Try removing the cap and inspecting the interior for any visible damage. This could be a simple fix if it's a crack.