cayenneS2004

P0446 code but no engine light?
2004 cayenne S v8
I bought durametric and just received it , excited i scaned my car and it came up with a p0446 code? But no engine light? Does anyone know if this is a big deal and what are the causes? Thanks!

grohgreg

P0446. Faults not accompanied by a persistent engine light are usually minor, hence self-resetting when the fault condition is no longer present. Major fault codes keep the check engine light on. All codes - regardless of severity - are retained in memory until manually deleted. So my guess is that your evap system burped at some point, threw a code and a brief engine light. You may have missed the engine light come on and go back off, as the fault was likely an isolated occurrence. It's safe to delete it with the Durametric.

//greg//

Loren

P0446 (for US cars) requires the light to be lit only after 2 drive cycles of the fault re-occurring (in this case testing good).
P0446 is EVAP canister shutoff valve faulty (sticks in closed state or is blocked) - so often it is clears itself.

cayenneS2004

What does the EVAP canister do? This is something i want to keep a eye on now

Loren

During normal venting operation the hydrocarbon laden fumes from the fuel in the fuel tank rise to the percolation tank via the tank vent lines and refueling vent line. The pressure in the tank is regulated to about 40 millibar by a vacuum-limiting valve so as not to allow the fuel to boil in the low pressure. The fumes stored in the EVAP canister where they are purged to the engine by the DME controlled EVAP
valve during purging. Thus the fumes are burned in the engine to reduce emissions.

EVAP systems have been required on US cars for many years to help reduce air pollution.