Emissions - Advanced DTC P02422/P0446 Diagnosis/Repair

VOLUME
3

GROUP
Fuel

NUMBER
006

MODEL
Sedona, Sorento
Optima, Amanti

DATE
December 2004

SUBJECT:
ENHANCED DIAGNOSIS AND REPAIR FOR P04461P2422

This bulletin provides information relating to diagnostic trouble code (DTC) P0446/P2422 (Scanner Description: EVAP System: Vent Control) for all Sedona, Sorento, Amanti and Optima (2.4L only) vehicles. The DTC P0446/P2422 sets when the fuel tank pressure sensor measures excessive vacuum in the fuel tank. P0446/P2422 is NOT related to a system leak. The Hi-Scan EVAP LEAK CHECK will NOT check for DTC P0446/P2422.

NORMAL SYSTEM OPERATION:

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 measureable amount of vacuum at the fuel tank pressure sensor during purging.

During the system leak check (the vehicle must be driving at a steady speed with engine RPM over 1800), the canister close valve shuts and purging occurs until the system is drawn to approximately 1.8 volts (measured at the fuel tank pressure sensor). The vacuum will remain at the specified value 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/P2422, 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/P2422 is set into ECM memory. If this condition occurs on two consecutive drive cycles, then the MIL will illuminate.





EVAPORATIVE EMISSION COMPONENTS:





Diagnostic Aid:

CCV Clogging Error (P0446/P2422) is detected when the fuel tank pressure goes below the specified threshold for longer than 10 seconds, the DTC will then be stored in the ECM. See chart threshold values, compare against recorded values.





SORENTO AND SEDONA TANK PRESSURE SENSOR CHART





AMANTI AND OPTIMA TANK PRESSURE SENSOR CHART





^ Restrictions in the shaded areas will set a DIG P0446 or P2422.

^ Inspect Canister Close Valve (CCV) for proper operation.

^ Inspect Vent Vacuum hoses for restrictions, spider webs, cocoon nests, kinks, etc.

^ Inspect the Fuel Tank Pressure Sensor (FTPS) atmospheric pressure port for restrictions, shipping cap.

Inspect air filter for clogging, use charts on pages 3 and 4 to determine filtering ability.