Gas tank/cap pressure?

[dlmack1]

Hey guys, quick question....when I remove my gas cap, there is no pressure....should I be hearing a "woooosh" sound? Also.....I have an error code P0455 "Fuel Tank Ventilation System (Major Leak)". Replaced the gas cap, not it. Here's the thing, I only get the CEL when the gas tank is half full and car is idling.......I can reset the light immediately, and the CEL will not come on again until I fill up, and the tank gets to half full. It never comes on twice per tank.....

So any ideas?....I hate to throw parts at .....evap purge valve?....carbon control valve?

Anyone have the same situation?

I did check the canister behind the wheel well....everything looks good, can't tell really though....no loose connections, everything looks "new" back there.

Thanks!

2000 Boxster base

2.7

71k

[pk2]

Hey guys, quick question....when I remove my gas cap, there is no pressure....should I be hearing a "woooosh" sound? Also.....I have an error code P0455 "Fuel Tank Ventilation System (Major Leak)". Replaced the gas cap, not it. Here's the thing, I only get the CEL when the gas tank is half full and car is idling.......I can reset the light immediately, and the CEL will not come on again until I fill up, and the tank gets to half full. It never comes on twice per tank.....

So any ideas?....I hate to throw parts at .....evap purge valve?....carbon control valve?

Anyone have the same situation?

I did check the canister behind the wheel well....everything looks good, can't tell really though....no loose connections, everything looks "new" back there.

Thanks!

2000 Boxster base

2.7

71k

[pk2]

Mine lets out more like a hiss that last about a second, You might find someone with a problem free 98x series and swap caps for a half an hour or so see what happens.

Regards, PK

[Loren]

P0445 EVAP Canister Purge Valve – Short to B+/Short to Ground

Potential causes:

– Wiring harness

– DME control module

Troubleshooting:

Check voltage supply for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect voltmeter (positive) to EVAP canister purge valve connector, pin 1, and ground.

3. Switch on the ignition.

Display: battery voltage

Check EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect ohmmeter to EVAP canister purge valve, pins 1 and 2.

Display: 26 ± 4 ohms at 20 °C.

Check triggering wire for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect special tool 9637 to wiring harness (DME control module connector).

3. Connect ohmmeter to EVAP canister purge valve, pin 2, and special tool 9637, pin III/3.

Display: 0 - 5 ohms

[dlmack1]

P0445 EVAP Canister Purge Valve – Short to B+/Short to Ground

Potential causes:

– Wiring harness

– DME control module

Troubleshooting:

Check voltage supply for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect voltmeter (positive) to EVAP canister purge valve connector, pin 1, and ground.

3. Switch on the ignition.

Display: battery voltage

Check EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect ohmmeter to EVAP canister purge valve, pins 1 and 2.

Display: 26 ± 4 ohms at 20 °C.

Check triggering wire for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.

2. Connect special tool 9637 to wiring harness (DME control module connector).

3. Connect ohmmeter to EVAP canister purge valve, pin 2, and special tool 9637, pin III/3.

Display: 0 - 5 ohms

Thanks for the info Loren....I appreciate your help!