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Cardoctor74, ASE Certified Technician
Category: Hyundai
Satisfied Customers: 25951
Experience:  Master ASE Technician
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Hyundai Santa Fe GLS: my check engine light came on and the

Resolved Question:

my check engine light came on and the santa fe seems to hesitate when accelerating. i had it checked at an auto zone and it came up with 2 codes: 1) P0306 which is misfire in cylinder 6 and 2) P0446 which is emmission system vent control valve circuit problem. what can be done??
Submitted: 5 years ago.
Category: Hyundai
Expert:  Cardoctor74 replied 5 years ago.
Does the vehicle misfire when at idle?
Customer: replied 5 years ago.
no, during idle it seems ok
Expert:  Cardoctor74 replied 5 years ago.
Ok there is a bulletin on this issue.
ModelXG300/350, 2.4L SONATA
Diagnostic trouble code P0446 (Scanner Description: EVAP System: Vent Control)
sets when the fuel tank pressure sensor measures excessive vacuum in the fuel tank.
P0446 is NOT related to a system leak. The Hi-Scan EVAP LEAK CHECK will NOT
check for a P0446.
In an evaporative emissions system, fuel vapors and air in the charcoal canister are
drawn into the intake manifold through the canister purge valve. The vapor/air drawn
from the charcoal canister is replenished by fresh air being drawn through the EVAP air
filter and canister close valve. Normally, there is a small but measurable amount of
vacuum at the differential pressure sensor during purging.
During the system leak check (the vehicle must be driving at a steady speed over 1800
RPM), the canister close valve shuts and purging occurs until the system is drawn to
1.8 volts (measured at the differential pressure sensor). The vacuum will remain at 1.8
volts for up to 30 seconds (depending on the fuel level). This is NORMAL operation,
and should not be confused with the diagnostic procedures described later.
In a system that sets P0446, the amount of vapors being purged from the canister is
greater than the volume of fresh air entering into the canister. This causes the canister
to build up vacuum. When the canister increases in vacuum, the remainder of the
system (fuel tank, hoses, separator, etc.) will also increase in vacuum. The fuel tank
pressure sensor measures and reports the vacuum level (in volts) to the ECM. If the
vacuum level reaches beyond the ECM threshold, P0446 is set into ECM memory. If
this condition occurs on two consecutive drive cycles, then the "Check Engine" light will
Evaporative Emission Components:
1. Canister Close Valve (CCV)
6. Charcoal Canister
5. CCV Air Filter
4. Fuel Cut Valve
3. Canister Purge Valve
2. Differential Pressure Sensor (DPS)
Most common is the canister close valve need to have an evap test to diagnose this correctly .This will also cause the misfire code.This is what needs to be checked next.Hoped this helped.Positive feedback and bonuses greatly appreciated.
Customer: replied 5 years ago.
ok, so if it is this canister close valve, what needs to be done next? does this need to be checked and fixed at a hyundai shop and how much would this usually cost? could it be the ccv air filter or something other than the canister valve?
Expert:  Cardoctor74 replied 5 years ago.
Any local shop can do this for you to save some money.It was listed in most common order .Should cost about 200 parts and labor the most.Hoped this helped.Positive feedback and bonuses greatly appreciated.
Customer: replied 5 years ago.
ok, is this something i can drive on for a little while or will more damage occure so it needs to be fixed asap??
Expert:  Cardoctor74 replied 5 years ago.
No its ok to drive and will not damamge the engine at all but get it fixed when you can.Hoped this helped.Positive feedback and bonuses greatly appreciated.
Cardoctor74 and 8 other Hyundai Specialists are ready to help you
Expert:  Cardoctor74 replied 5 years ago.
Did you need anything else?