P0455-tighten Fuel Cap Fix

[06ado]

My 06 Silverado Crew Cab with 5.3 engine (38,000 miles) has given me several Tighten Fuel Cap messages and a CEL. Cap is good...even removed gasket from cap and cleaned it and filler neck. Had code checked. It shows P0455. Before I spend the money is this indicative of the evap. vent solenoid problem? I've seen references that indicate this is the fix for a P0449 code NOT a P0455 code. I plan on checking the code again at AutoZone but so far it only shows P0455. I just don't want to replace parts and not have that fix the issue.

 

Any suggestions or advice would be welcome.

 

Thanks.

 

Mike in AL

[RyanbabZ71]

How do you know the cap is good? I had a CEL light on my 08 Tahoe with less than 2K miles and the cap ended up being defective, it wasnt sealing properly but I couldnt tell from normal operation.

[wages999]

I had a broken wire going to the evap vent solenoid that caused my truck to throw a code for the gas cap and the evap vent solenoid. From what I've read, it sounds like your problem could easily be a defective gas cap if your only code is for the gas cap.

[BigBlueLB756]

PO455 - EVAP system - large leak detected

 

PO449 - EVAP system - vent solenoid control circuit

 

Get a new cap. If that doesn't fix it, at least you'll have a spare.

[Bob D]

These codes can be pesky, in that it takes a lot of "driving cycles" for the code to clear (assuming the problem is fixed). Over a week in some cases.

How do you know cap is good? Pressure test?

[06ado]

Everyone is a great help. Sounds like the consensus is that it likely is the cap. The CEL isn't on now. It comes and goes as does the Tighten Cap message as well but since it happens intermittently maybe it is a problem with the cap so I guess I'll get a new one. I'm going to get the code checked today again at AutoZone just to see if it's still showing P0455 and only P0455.

 

Any recommendations on source or are these best purchased through a dealer?

 

Thanks,

 

Mike

[Bob D]

...the Tighten Cap message...

Do bear in mind that the p0455 code is NOT a "tighten cap" code (although a loose / faulty cap is often the cause). It means a large leak has been detected.

If you replace cap, suggest you clear code. Otherwise it may take a week or longer for code to clear on it's own.

[neto1978]

had the same problem, replaced vent valve and canister.

 

My 06 Silverado Crew Cab with 5.3 engine (38,000 miles) has given me several Tighten Fuel Cap messages and a CEL. Cap is good...even removed gasket from cap and cleaned it and filler neck. Had code checked. It shows P0455. Before I spend the money is this indicative of the evap. vent solenoid problem? I've seen references that indicate this is the fix for a P0449 code NOT a P0455 code. I plan on checking the code again at AutoZone but so far it only shows P0455. I just don't want to replace parts and not have that fix the issue.

 

Any suggestions or advice would be welcome.

 

Thanks.

 

Mike in AL

[06ado]

Is this the Evap vent solenoid? Can you tell me what partnumbers you purchased and where you bought them from?

 

I found this on Amazon. Is this what I need to replace in addition to the cannister?

 

http://www.amazon.com/dp/B000S2SKIY/ref=pe...24030_pe_vfe_d1

 

Thanks,

 

Mike

[neto1978]

exactly this one, I replaced the egr valve on the engine too, but the problem was this one that you found at amazon!

 

Is this the Evap vent solenoid? Can you tell me what partnumbers you purchased and where you bought them from?

 

I found this on Amazon. Is this what I need to replace in addition to the cannister?

 

http://www.amazon.com/dp/B000S2SKIY/ref=pe...24030_pe_vfe_d1

 

Thanks,

 

Mike

[Bob D]

...Is this the Evap vent solenoid?...Is this what I need to replace in addition to the cannister?...

Mike, you're too anxious to start throwing money at this thing.

1) Does the gas cap replacement cure the issue? If no:

2) Bench test the Vent Valve. If it fails, replace. If it tests OK:

3) Check hoses, fuel tank inlet, etc.

[06ado]

OK, seems like the first step is to replace the gas cap and see if that fixes the problem. Then bench test the evap solenoid. To do that are you saying just put 12VDC to it to verify it opens and closes?

[Bob D]

OK, seems like the first step is to replace the gas cap and see if that fixes the problem. Then bench test the evap solenoid. To do that are you saying just put 12VDC to it to verify it opens and closes?

Yup.

You may want to clear the code after each corrective action. (It'll take a week or more for the computer to verify correct operation of the evap system.)

If gas gap replace doesn't work, bench test valve with 12VDC. Make sure it opens and closes tightly / doesn't leak. Bang it around / blow it out to see if there is any dirt / debris in it.

[kevin.t.poe]

OK, seems like the first step is to replace the gas cap and see if that fixes the problem. Then bench test the evap solenoid. To do that are you saying just put 12VDC to it to verify it opens and closes?

Yup.

You may want to clear the code after each corrective action. (It'll take a week or more for the computer to verify correct operation of the evap system.)

If gas gap replace doesn't work, bench test valve with 12VDC. Make sure it opens and closes tightly / doesn't leak. Bang it around / blow it out to see if there is any dirt / debris in it.

 

 

 

When testing is this valve normally open at 0v or open at 12v?

 

Kevin Poe

04 Suburban 2500 8.1L (with P0455 code and a solenoid valve that is open with no voltage)