2000 elantra po455 code evap emission control system leak detected (gross leak) Any suggestions ?

P0455- Evap Emission Ctrl Sys Gross Leak Detected
P0496 Evaporative Emission Sys High Purge Flow
This is the 2 codes you requested and they say you have a leak in the emission sys.

P0455: Evaporative Emission Control System Leak Detected Gross Leak 1
P0455 Evaporative Emission Control System Leak Detected Gross Leak

P0141: O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2
P0141 O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2

Possible causes
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
What does this mean? Tech notes
The P0455 it's a very common code, because the code is set if the gas cap is loose or missing. Start by tighten the gas cap and clearing the code. In most cases the code can be clear by disconnecting the car battery for about 30 minutes.
What does this mean? When is the code detected?
Evaporative Emission System (EVAP) control system has a very large leak such as fuel filler cap fell off, EVAP control system does not operate properly.
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible a noticeable fuel odor caused by the release of fuel vapors
P0455 Mitsubishi Description
This diagnosis detects leaks in the Evaporative Emission System (EVAP) purge line using engine intake manifold vacuum. If pressure does not increase, the Engine Control Module (ECM) will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition.
The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.

Read more: http://engine-codes.com/p0455_mitsubishi.html#ixzz3NlVyARyX

jeep uses whats called a leak detection pump that is the most common failure in the system that i have seen in the last five yeas

P0455 CHEVROLET - Evaporative Emission Control System Leak Detected Gross Leak3http://engine-codes.com/p0455_chevrolet.htmlForum CodePossible causes- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking

P0496 is not alisted code.
P0455 - Evaporative Emission Control System Leak Detected Gross Leak (fuel vapors)
Symptoms - Engine Light ON (or Service Engine Soon Warning Light)
- Possible a noticeable fuel odor caused by the release of fuel vapors Possible causes - Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking

P0305....Cylinder 5 Misfire Detected

P0442....Evaporative Emission Control System Leak Detected (small leak)

P0455....Evaporative Emission Control System Leak Detected (gross leak)

The OBD P0455 Code refer to Evaporative Emission (EVAP) control system gross leak detected.

its possible that you need a new Vent Vontrol Valve. The part # is 14935-am60a. It costs around $100.00

Hope help with this.

CODE PO455 EVAPORATIVE EMISSION SYSTEM LARGE LEAK DETECTED.POSSIBLE CAUSES CANISTER VENT SOLENOID MAY BE STUCK IN OPEN POSITION / EVAP CANISTER TUBE EVAP CANISTER PURGE OUTLET TUBE OR EVAP RETURN TUBE DISCONNECTED OR CRACKED OR CANISTER IS DAMAGED / EVAP CANISTER PURGE VALVE STUCK CLOSED OR CANISTER DAMAGED / FUEL FILLER CAP MISSING LOOSE NOT TIGHT OR THE WRONG PART / FUEL VAPOR HOSES TUBES BLOCKED OR RESTRICED OR FUEL VAPOR CONTROL VALVE TUBE OR FUEL VAPOR VENT VALVE ASSEMBLY BLOCKED /FUEL TANK PRESSURE SENSOR HAS FAILED MECHANICAL FAULT /FUEL TANK CONTROL VALVE IS CONTAMINATED DAMAGED OR HAS FAILED.

First thing to check is the gas cap, make certain it is tight and the cap seal is not damaged or cut. In many cases this is the root cause for the P0455.
If that checks good, you want to check the vacuum hoses from the EVAP purge solenoid under the hood, all the way back to the EVAP canister. Make certain all are connected and not damaged or cracked.
Let me know.
Regards,