P0446
DTC P0446: Evaporative Emission Control System Vent Control CircuitEvaporative Emission Ventilation Solenoid Circuit Part 1:
Evaporative Emission Ventilation Solenoid Circuit Part 2:
CIRCUIT OPERATION
- The evaporative emission ventilation solenoid power is supplied from the MFI relay (terminal No. 4).
- The ECM
TECHNICAL DESCRIPTION
- To judge if there is open circuit in the evaporative emission ventilation solenoid drive circuit, ECM
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Off-surge does not occur after solenoid is operated on to off.
MONITOR EXECUTION
Once per driving cycle
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored )
- Not applicable
Sensor (The sensor 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 ventilation solenoid coil surge voltage (battery positive voltage + 2 volts) is not detected for 0.2 second.
- The ECM
Check Conditions
- Battery positive voltage is at between 10 and 16.5 volts.
- ON duty cycle of the evaporative emission purge solenoid is 0 percent.
- ON duty cycle of the EGR vacuum regulator solenoid valve is 0 percent.
- Evaporative emission ventilation solenoid is ON.
- More than 1 second has elapsed after the above mentioned conditions have been met.
Judgment Criteria
- The evaporative emission ventilation solenoid coil surge voltage (battery positive voltage + 2 volts) is not detected for 1 second. When the evaporative emission ventilation solenoid is turned OFF.
OBD-II DRIVE CYCLE PATTERN
Refer to, Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Evaporative emission ventilation solenoid failed.
- Open or shorted evaporative emission ventilation solenoid circuit, or harness damage, or connector damage.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check actuator test item 29: Evaporative Emission Ventilation 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 29, Evaporative emission ventilation solenoid.
- An operation sound should be heard and vibration should be felt when the evaporative emission ventilation 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. Refer to How to Use Troubleshooting/ Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check connector D-10 at the evaporative emission ventilation solenoid for damage.
Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 3. Check the evaporative emission ventilation solenoid.
1. Disconnect the evaporative emission ventilation solenoid connector D-10.
2. Measure the resistance between evaporative emission ventilation solenoid side connector terminal No. 1 and No. 2.
Standard value: 17 - 21 Ohms [at 20 °C (68 °F)]
Q: Is the resistance between 17 and 21 Ohms?
YES: Go to Step 4.
NO: Replace the over vent valve module. Then go to Step 12.
STEP 4. Check the power supply voltage at evaporative emission ventilation solenoid harness side connector D-10.
1. Disconnect the connector D-10 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 connector A-18X at MFI relay for damage.
Q: Is the connector in good condition?
YES: Check connectors C-28, C-90 and D-16 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors are in good condition, repair harness wire between MFI relay connector A-18X (terminal No. 4) and evaporative emission ventilation solenoid connector D-10 (terminal No. 2) because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 6. Check the power supply voltage at ECM connector C-51
1. Do not disconnect the connector C-51
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 35 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 connector C-51 at ECM
Q: Is the connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 8. Check for open circuit and short circuit to ground between evaporative emission ventilation solenoid connector D-10 (terminal No. 1) and ECM connector C-51 (terminal No. 35)
NOTE: Check harness after checking intermediate connectors C-28, C-90 and D-16. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 12.
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 9. Check connector C-51 at ECM
Q: Is the connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 10. Check for harness damage between MFI relay connector A-18X (terminal No. 4) and evaporative emission ventilation solenoid connector D-10 (terminal No. 2).
NOTE: Check harness after checking intermediate connectors C-28, C-90 and D-16. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 12.
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 ventilation solenoid connector D-10 (terminal No. 1) and ECM connector C-51 (terminal No. 35)
NOTE: Check harness after checking intermediate connectors C-28, C-90 and D-16. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 12.
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. 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 - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0446 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.