P0444
DTC P0444 EVAP EMISSION SYSTEM-PURGE CTRL. VALVE CIRCUIT OPENComponent Location:
COMPONENT LOCATION
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 from the canister to the intake manifold.
DTC DESCRIPTION
If the surge and output voltage is satisfied with threshold value, the PCM determines that a fault exists and a DTC is stored.
DTC Detecting Condition:
MONITOR SCANTOOL DATA
1. Warm-up engine to normal operating temperature.
NOTE: Evaporative Emissions Systems (EVAP) Leak Tests can be run by the Scan Tool. The tests are automated and provide either a pass-Fail result or directions to check for DTCs.
2. Install scan tool and perform "05 EVAP. LEAKAGE TEST" mode referring to enable conditions as above.
3. Monitoring for (pending) DTC by performing "01. DIAGNOSTIC TROUBLE CODES" or "04. MONITORING TEST RESULTS". Is the same DTC set?
YES: Go to "System Inspection" procedure.
NO: Fault is intermittent caused by poor contact in Sensor's and/or PCM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification vehicle Repair" procedure.
TERMINAL & 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 SUPPLY CIRCUIT INSPECTION
1. Check power to PCSV
1. Ignition "ON" & Engine "OFF"
2. Disconnect PCSV connector.
3. Ignition " ON " & Engine "OFF"
4. Measure voltage between terminal "2" of PCSV harness connector and chassis ground.
Specification: B+
5. Is the measured voltage within specifications?
YES: Go to "Control Circuit Inspection" procedure.
NO:
- Check open or short to ground in harness between control relay and PCSV.
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
CONTROL CIRCUIT INSPECTION
1. Check for short to ground in harness
1. Ignition "OFF"
2. Disconnect PCSV connector.
3. Measure resistance between terminal "1" of PCSV harness connector and chassis ground.
Specification: Infinite
4. Is the measured resistance within specifications?
YES: Go to" Check for open in harness" as below.
NO:
- Check short to ground in signal harness.
- Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.
2. Check for open in harness
1. Ignition "OFF"
2. Disconnect PCSV and PCM connector.
3. Measure resistance between terminal "1" of PCSV harness connector and terminal "34" of PCM harness connector.
Specification: Approx. below 1 Ohms
4. Is the measured resistance within specifications?
YES: Go to " Component Inspection "procedure.
NO:
- Check open in harness between PCSV connector and PCM connector.
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Check PCSV
1. Ignition "OFF"
2. Measure resistance between terminals "1" and "2" of the PCSV connector.
Specification: Approx. 24 - 28 Ohms (20 °C (68 °F))
3. Monitor the PCSV signal waveform and verify that the ground voltage is less than approx. 0.3 V (I) and the surge voltage (Z) is between 40 V and 60 V
4. Perform Actuation Test for PCSV with scantool.
5. Is the PCSV working properly?
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.
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 tests 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.