P1444
SYSTEM DESCRIPTION
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass passage in the EVAP canister purge volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions. When the engine is operating, the flow rate of fuel vapor from the EVAP canister is regulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control valve uses a step motor to control the flow rate of fuel vapor from the EVAP canister. This motor has four winding phases. It operates according to the output pulse signal of the ECM. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECM does not issue the pulse signal. A certain voltage signal is issued so that the valve remains at that particular opening.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values and are measured between each terminal and engine ground
ON BOARD DIAGNOSIS LOGIC
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a safe speed.
NOTE: If "DTC CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
TESTING CONDITION: Always perform test at a temperature above 5°C (41°F).
With Consult
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON".
4. Select "PURG CN/V & S/V P1493" of "EVAPORATIVE SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT.
5. Touch "START".
6. Start engine and let it idle for at least 90 seconds.
7. When the following conditions are met, "TESTING" will be displayed on the CONSULT screen. Maintain the conditions continuously until "TESTING" changes to "COMPLETED". (It will take at least 30 seconds.)
Selector lever: Suitable position
Vehicle speed: 36 - 120 KPH (22 - 75 MPH)
CMPS.RPM (REF):1,200 rpm or more (A/T) 1,600 rpm or more (M/T)
B/FUEL SCHDL: 1 - 4.5 msec
8. Stop vehicle with engine running.
9. Select "PURG VOL CN/V P1444" of "EVAPORATIVE SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT.
10. Touch "START".
If "COMPLETED" is displayed, go to step 12.
11. When the following conditions are met, "TESTING" will be displayed on the CONSULT screen. Maintain the conditions continuously until "TESTING" changes to "COMPLETED". (It will take at least 20 seconds.)
Selector lever: Suitable position
Vehicle speed: 36 - 120 KPH (22 - 75 MPH)
CMPS.RPM (REF): 1,200 rpm or more (A/T) 1,600 rpm or more (M/T)
B/FUEL SCHDL: 1 - 4.5 msec
NOTE: If "TESTING" is not displayed after 5 minutes, retry from step 2.
12. Make sure that "OK" is displayed after touching "SELF-DIAG RESULTS". If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE".
OR
With Generic Scan Tools
1. Lift up vehicle.
2. Start engine and warm it up to normal operating temperature.
3. Select "MODE 1" with GST.
4. Check coolant temperature.
Coolant temperature: 40 - 100°C (104 - 212°F) Be sure that water temperature does not exceed 100°C. If it becomes higher than 100°C, cool down the engine and perform the procedure again from the beginning.
5. Turn ignition switch "OFF" and wait at least 5 seconds.
6. Restart engine and let it idle for at least 100 seconds.
7. Maintain the following conditions for at least 80 seconds.
Gear position: Suitable gear position
Vehicle speed: 36 - 120 KPH (22 - 75 MPH)
Engine speed: 1,200 rpm or more (A/T) 1,600 rpm or more (M/T)
Coolant temperature: 40 - 100°C (104 - 212°F)
8. Select "MODE 7" with GST.
9. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
NOTE:
- Hold the accelerator pedal as steady as possible during driving in step 7.
- If the driving conditions are not satisfied in step 7 restart the procedure.
- It is better that the fuel level is low.
OR
Without Consult
1. Lift up vehicle.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal (51) and engine ground
Voltage: 0.8 - 1.5 V
Perform the following procedure before the voltage drops below 0.8 V. If the voltage drops below 0.8 V, cool down the engine and perform the entire procedure all over again.
4. Turn ignition switch "OFF" and wait at least 5 seconds.
5. Restart engine and let it idle for at least 100 seconds.
6. Maintain the following conditions for at least 80 seconds.
Gear position: Suitable gear position
Vehicle speed: 36 - 120 KPH (22 - 75 MPH)
Engine speed: 1,200 rpm or more (A/T) 1,600 rpm or more (M/T)
Check voltage between ECM terminal (51) and engine ground: 0.8 - 1.5 V
7. Turn ignition switch "OFF", wait at least 5 seconds, and then turn "ON".
8. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
9. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
NOTE:
- Hold the accelerator pedal as steady as possible during driving in step 6.
- If the driving conditions are not satisfied in step 6 restart the procedure.
- It is better that the fuel level is low.
DIAGNOSIS PROCEDURE
COMPONENT INSPECTION
EVAP canister purge volume control valve
With Consult
1. Disconnect EVAP canister purge volume control valve harness connector.
2. Check resistance between the following terminals.
terminal (2) and terminals (1), (3)
terminal (6) and terminals (4), (6)
Resistance: Approximately 35 - 43 Ohm [At 20°C (68°F)]
3. Reconnect EVAP canister purge volume control valve harness connector.
4. Remove EVAP canister purge volume control valve from intake manifold collector and disconnect hoses from the valve.
(Plug the purge hoses. The EVAP canister purge volume control valve harness connector should remain connected.)
5. Turn ignition switch "ON".
6. Perform "PURG VOL CONT/V" in "ACTIVE TEST" mode with CONSULT. Check that EVAP canister purge volume control valve shaft moves smoothly forward and backward according to the valve opening.
If NG, replace the EVAP canister purge volume control valve.
OR
Without Consult
1. Disconnect EVAP canister purge volume control valve harness connector.
2. Check resistance between the following terminals.
terminal (2) and terminals (1),(3)
terminal (5) and terminals (4),(6)
Resistance: Approximately 35 - 43 Ohm [At 20°C (68°F)]
3. Reconnect EVAP canister purge volume control valve harness connector.
4. Remove EVAP canister purge volume control valve from intake manifold collector and disconnect hoses from the valve.
(Plug the purge hoses. The EVAP canister purge volume control valve harness connector should remain connected.)
5. Turn ignition switch "ON" and "OFF". Check that EVAP canister purge volume control valve shaft moves smoothly forward and backward according the ignition switch position.
If NG, replace the EVAP canister purge volume control valve.
EVAP control system pressure sensor
1. Remove EVAP control system pressure sensor with its harness connector connected.
2. Remove hose from EVAP control system pressure sensor.
3. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
4. Check output voltage between ECM terminal (67) and engine ground.
CAUTION:
- Always calibrate the vacuum pump gauge when using it.
- Do not apply pressure below -20 kPa (-150 mmHg, -5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg).
5. If NG, replace EVAP control system pressure sensor.
EVAP canister vent control valve
Check air passage continuity.
With Consult
Perform "VENT CONTROL/V" in "ACTIVE TEST" mode with CONSULT
OR
Without Consult
If NG or operation takes more than 1 second, clean valve using air blower or replace as necessary.
If the portion (B) is rusted, replace EVAP canister vent control valve.
Make sure new O-ring is installed properly.