Circuit Description
Once every drive cycle, the EVAP system runs a 25-40 second diagnostic
where it monitors possible leaks, the fuel tank pressure sensor, vent valve, and canister
purge valve. This diagnostic has five phases and can set several different codes depending
on which part of the diagnostic fails. This code can set in the 2nd phase if
tank pressure falls while the vent and purge valves are both commanded shut. It will
also set in the 4th phase if the pressure falls below a calibrated value too
quickly. This code indicates that the purge valve is stuck open.
DTC Parameters
DTC 1441 will set when:
| • | Fuel system in closed loop |
| • | Battery Voltage great than 11.0 volts |
| • | Engine Run Time greater than 1 minute and 45 seconds |
| • | Altitude less than 9000 ft. |
| • | Fuel Level between 1.8 and 14 gal |
| • | No TP, ECT, VSS, Tank pressure, oxygen sensor, idle control, purge valve,
vent valve, battery voltage, misfire or EGR codes set |
P1441 is a (type B) DTC.
Diagnostic Aids
Possible causes:
| • | EVAP purge solenoid stuck open |
| • | EVAP purge solenoid circuit 428 intermittently shorted to ground
or ECM intermittently shorted to ground internally on that circuit. |
NOTE: If DTC P0455 is set, diagnose it first.
