The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustion. This valve is actuated by the purge control signal from the ECM and controls fuel vapor from the canister to the intake manifold.
ECM sets DTC P0444 if the ECM detects that the PCSV control line is open.
Item
Detecting Condition
Possible cause
DTC Strategy
? Circuit continuity check, low
? Open in battery circuit
? Open in control circuit
? Short to ground in control circuit
? Faulty PCSV
? Faulty ECM
Threshold value
? Short circuit to GND or disconnected
Enable Conditions
-
Diagnostic Time
? Continous
Purge Control Solenoid Valve
Normal Parameter At 20?(68°F)
Resistance
24.5 ~ 27.5 ?
Hi-scan Data display
Idle
0%
1000 ~ 3000 rpm
1.5 ~ 35 %
This is waveform measured at terminal 2 of PCSV under no-load,1500 RPM.
The voltage at point ? is 14 V.
Possible cause:No power supply or open in PCSV.
Point ? is a surge voltage when power TR is off and about 45 V.
Periode ? is the duration when PCSV operates and usually operating duty value is about 15 % in 2000RPM.
Periode ? is duty per 1Hz and ON-OFF ratio of TR in ECM.