P0446

1999 Boxster

It threw a P0446 code today while driving. I'm fairly certain I had this same code about 4 months ago. At that time, I cleared the code. Took another 4 months for it to show up again. Thoughts on the issue?

Greg
1999 Boxster

Grant

gee-lenahan-at-gee-mail-dot-com

EVAP canister shutoff valve below limit.

Greg
1999 Boxster

and the error reappears so infrequently, I'd be inclined to find the vent valve and disconnect and reconnect its electrical connectors in the belief (hope) that some marginal surface corrosion is causing excessive resistance on the vent valve control circuit.

The code can also arise if the evaporative system test is unable to create or sustain a suitable low pressure. This then is a leak somewhere. Again I have to think about the age of the car and the possibility a hose has developed a crack or a split due to age.

Then it could just be a gas cap seal is not sealing 100%. Up to you but may be a new gas cap is worth the cost and trouble to replace?

Thanks, Marc. Any idea where the vent valve is physically located? I know that the canister that it connects to is behind the right front wheel well.

P0446 Below lower limit – Purge air line blocked
– Flow resistance of EVAP canister too high
Note
Fuel tank ventilation can be activated with the Porsche System Tester 2 in the Short test menu.

On-Board Diagnostic
Boxster Troubleshooting
1999 Supplement 3 P0446 - 1 System Overview 673_97
1 – EVAP canister purge valve
2 – EVAP canister
3 – Purge air
4 – Tank
5 – Pressure sensor
6 – Shutoff valve
7 – Operating purge valve
8 – To intake manifold
9 – Vacuum control valve

Troubleshooting
Boxster On-Board Diagnostic
P0446 - 2 Supplement 3 1999

Diagnosis Procedure 1
Check purge air line for blockage.
OK
Repair purge air line.
End
Replace EVAP canister.
End
Not OK
On-Board Diagnostic
Boxster Troubleshooting
1999 Supplement 3 P0446 - 3
1. Check purge air line for blockage.
1. Remove front right-hand wheel housing liner.
2. Detach purge air line (connection face up) from EVAP canister.
3. Blow through purge air line with compressed air.
Troubleshooting
Boxster On-Board Diagnostic P0446

Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Thanks, Pedro. I'll start with that purge line and go from there.

Pedro,

I received both codes 0446 and 0447 when the car is cold and at idle or when I slow down in the mornings. My research suggest the Y split on the vacuum hose. 2004 Boxster S 118K miles runs great. any ideas?

You may want to start a new thread with your question because this thread is old and if no one is monitoring it, they won't see your post. That said, I traced my issue to a gas cap that is going bad as it would happen within miles of filling up with gas and then eventually go away.

Thanks will do, had the gas cap replaced about 1 year ago.