P0443
DTC P0443: Evaporative Emission Control System Purge Control Valve CircuitEvaporative Emission Purge Solenoid Circuit Part 1:
Evaporative Emission Purge Solenoid Circuit Part 2:
CIRCUIT OPERATION
- Power to the evaporative emission purge solenoid power is supplied from the MFI relay (terminal No.4).
- The ECM controls ground evaporative emission purge solenoid by turning the power transistor in the ECM "ON" and "OFF".
TECHNICAL DESCRIPTION
- To judge if there is open circuit in the evaporative emission purge solenoid drive circuit, ECM measures the surge voltage of the evaporative emission purge solenoid coil.
- The ECM drives the evaporative emission purge solenoid. After the solenoid is turned off, the ECM will check if the solenoid coil produces a surge voltage of 2 volts or more.
DESCRIPTIONS OF MONITOR METHODS
- Off-surge does not occur after solenoid is operated from on to off.
MONITOR EXECUTION
- Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Engine is being cranked.
- Battery positive voltage is at between 10 and 16.5 volts.
Judgment Criteria
- The evaporative emission purge solenoid coil surge voltage (battery positive voltage +2 volts) is not detected for 0.2 second.
- The ECM monitors for this condition once during the drive cycle.
Check Conditions
- Battery positive voltage is at between 10 and 16.5 volts.
- ON duty cycle of the evaporative emission purge solenoid is between 10 and 90 percent.
- ON duty cycle of the EGR vacuum regulator solenoid valve is 0 percent.
- Evaporative emission ventilation solenoid is OFF.
- More than 1 second has elapsed after the above mentioned conditions have been met.
Judgment Criterion
- The evaporative emission purge solenoid coil surge voltage (battery positive voltage +2 volts) is not detected for 1 second. When the evaporative emission purge solenoid is turned OFF.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Evaporative emission purge solenoid failed.
- Open or shorted evaporative emission purge solenoid circuit, harness damage, or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check actuator test item 08: Evaporative Emission Purge Solenoid.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the actuator test mode for item 08, Evaporative Emission Purge Solenoid.
- An operation sound should be heard and vibration should be felt when the evaporative emission purge solenoid is operated.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the solenoid operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.
STEP 2. Check harness connector B-02 at the evaporative emission purge solenoid for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Then go to Step 12.
STEP 3. Check the evaporative emission purge solenoid.
1. Disconnect the evaporative emission purge solenoid connector B-02.
2. Measure the resistance between evaporative emission purge solenoid side connector terminal No.1 and No.2.
Standard value: 30 - 34 Ohms [at 20 degrees C (68 degrees F)]
Q: Is the measured resistance between 30 and 34 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 4.
NO: Replace the evaporative emission purge solenoid. Then go to Step 12.
STEP 4. Measure the power supply voltage at evaporative emission purge solenoid harness side connector B-02.
1. Disconnect connector B-02 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.2 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 6.
NO: Go to Step 5.
STEP 5. Check harness connector B-12X at MFI relay for damage.
Q: Is the harness connector in good condition?
YES: Repair harness wire between MFI relay connector B-12X (terminal No.4) and evaporative emission purge solenoid connector B-02 (terminal No.2) because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Then go to Step 12.
STEP 6. Measure the power supply voltage at ECM connector C-121 by backprobing.
1. Do not disconnect connector C-121.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.16 and ground by backprobing.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 9.
NO: Go to Step 7.
STEP 7. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Then go to Step 12.
STEP 8. Check for open circuit and short circuit to ground between evaporative emission purge solenoid connector B-02 (terminal No.1) and ECM connector C-121 (terminal No.16).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 9. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it. Then go to Step 12.
STEP 10. Check for harness damage between MFI relay connector B-12X (terminal No.4) and evaporative emission purge solenoid connector B-02 (terminal No.2).
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Check for harness damage between evaporative emission purge solenoid connector B-02 (terminal No.1) and ECM connector C-121 (terminal No.16).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0443 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.