Help Needed!!! (P0446: Evap Emission Control System Vent Control Circuit)

[drmagieed]

I had P0446: Evaporative Emission Control System Vent Control Circuit last tuesday and once I cleared the DTC it went out. But today Saturday at the morining (the Car was off for more than 36 hours) the code come again 2 minutes after I run the car. I clearded the DTC again it went out.
What is the problemn I had or this is normal?
Thanks.

[Daox]

Sounds like a bad evap solenoid.

P0446 Evaporative Emmission Control System Vent Control Circuit

What does that mean?
Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Batt. voltage with key on.
The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test.

Symptoms
There will be no obvious symptoms to driver, other than Malfunction Indicator Lamp (MIL) illumination.

Causes
A code P0446 could mean one or more of the following has happened:
Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM

Read more at: P0446 Evaporative Emission Control System Incorrect Purge Flow
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[drmagieed]

Thanks, but when I clearing the DTC it went out and never come back for until today (tuseday).

[xintersecty]

Thanks, but when I clearing the DTC it went out and never come back for until today (tuseday).

I have the same problem with my truck. You clear and it takes a while for it to come back. Some of the diagnostics in ODBII are binary and some use a trend. So when I clear my evap pressure on the truck it takes about four days. So it's time to take DOAX advice and replace a purge valve.

[drmagieed]

I have the same problem with my truck. You clear and it takes a while for it to come back. Some of the diagnostics in ODBII are binary and some use a trend. So when I clear my evap pressure on the truck it takes about four days. So it's time to take DOAX advice and replace a purge valve.

Thanks, you mean vent valve?

[drmagieed]

For better information to take the decision to change the vent valve, I attached the freez frame of the P0446 on my car.
I hope to help me to take the decision.
Thanks.

[xintersecty]

Yes the vent valve

[drmagieed]

I noticed that the code come back every 3 days but today it came with p0462 code: fuel level sensor circuit low input.. What does this mean?

[xintersecty]

It means there is something broken.
P0462 Fuel Level Sensor Circuit Low Input | AutoCodes

The vent solenoid and the fuel sensor might be on the same circuit. You should check the grounds and make sure the wiring in that section is good.

[drmagieed]

I replaced the vent valave and the code come again. I think if I need to replace the fuel filler neck?