P0444

DTC P0444






GENERAL DESCRIPTION
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 PCM 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 PCM and controls fuel vapor flow the canister to the intake manifold.

DTC DESCRIPTION
Checking output signals from PCSV every 10 sec. under detecting condition, if signals indicating open or short to ground in the circuit are detected for more than 5 sec., PCM sets P0444. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition:

DTC DETECTING CONDITION

SPECIFICATION
Item Coil resistance(ohms)
Injector 19.0 - 22.0 ohms at (20 °C / 68 °F)

Schematic Diagram:

SCHEMATIC DIAGRAM




SIGNAL WAVEFORM AND DATA

MONITOR SCANTOOL DATA
1. Connect Scantool to Data Link Connector. (DLC)
2. Warm up engine to normal operating temperature.




3. Monitor "PCSV" parameter on the Scantool.
4. Is the current data displayed correctly?

YES - Fault is intermittently caused by poor contact in the sensor and/or PCM connector or non cleared PCM memory after repair. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace if necessary and go to "Verification of vehicle Repair".

NO - Go to "Terminal and Connector Inspection" procedure.

TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination,deterioration, or damage.
3. Has a problem been found?

YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO - Go to " Power Circuit Inspection " procedure.

POWER CIRCUIT INSPECTION
1. IG "OFF" and disconnect PCSV connector.
2. IG "ON" and ENG "OFF"




3. Measure voltage between terminal 1 of PCSV harness connector and chassis ground.

Specification : B+

4. Is the measured voltage within specification?

YES - Go to "Control Circuit Inspection" procedure.

NO - Repair open or short to ground in harness, and go to " Verification of Vehicle Repair" procedure.

CONTROL CIRCUIT INSPECTION
1. Check short to ground in harness.
a. IG "OFF" and disconnect PCSV connector.
b. IG "ON"




c. Measure voltage between terminal 2 of PCSV harness connector and chassis ground.

Specification : Approx. 0.5 V

d. Is the measured voltage within specification?

YES - Go to "Check open in harness" as follows.

NO - Repair short to ground in harness, and go to " Verification of Vehicle Repair" procedure.

2. Check open in harness.
a. IG "OFF" and disconnect PCSV connector and PCM connector.




b. Measure resistance between terminal 2 of PCSV harness connector and terminal 78 of PCM harness connector.

Specification : Below 1 ohm

c. Is the measured resistance within specification?

YES - Go to " Component Inspection" procedure.

NO - Repair open in harness, and go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION
1. Check PCSV
a. IG "OFF" and disconnect PCSV connector.




b. Measure resistance between terminals 1 and 2 of PCSV connector.(Component side)

Specification:
Item Coil resistance(ohms)
Injector 19.0 - 22.0 ohms at (20 °C / 68 °F)

c. Is the measured resistance within specification?

YES - Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.

NO - Substitute with a known - good PCSV and check for proper operation. If the problem is corrected, replace PCSV and go to "Verification of Vehicle Repair" procedure.

NOTE: There is a memory reset function on Scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others

VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all readiness test have been verified as "Complete".
5. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System is performing to specification at this time.