DTC P0443: Evaporative Emission Control System Purge Control Valve Circuit

CIRCUIT OPERATION

• The evaporative emission purge solenoid power is supplied from the MFI relay (terminal No. 2).
  
• 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, the ECM measures the surge voltage of the evaporative emission purge solenoid coil.
  

DESCRIPTIONS OF MONITOR METHODS

Off-surge does not occur after solenoid is operated from on to off.

MONITOR EXECUTION

Once per driving cycle.

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

• Not applicable
  

• Not applicable
  

DTC SET CONDITIONS

• Engine is being cranked.
  
• Battery positive voltage is between 10 and 16.5 volts.
  

• 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.
  

• Battery positive voltage is between 10 and 16.5 volts.
  
• ON duty cycle of the evaporative emission purge solenoid is between 10 and 90 percent.
  
• Evaporative emission ventilation solenoid is off.
  
• More than 1 second has elapsed after the above mentioned conditions have been met.
  

• The evaporative emission purge solenoid coil surge voltage (battery positive voltage + 2 volts) is not detected for 1 second after the evaporative emission purge solenoid is turned off.
  

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .

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.
  

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 10, 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? It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How Cope with Intermittent Malfunctions . Go to Step 2.

	Go to Step 3.

	Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 10.

(2)Measure the resistance between evaporative emission purge solenoid side connector terminal No. 1 and No. 2. Standard value: 22 - 26 Ω [at 20°C (68°F)] Q. Is the measured resistance between 22 and 26 Ω [at 20°C (68°F)]? Go to Step 4. Replace the evaporative emission purge solenoid. Then go to Step 10.

(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? Go to Step 6. Go to Step 5.

Check harness connector A-10 at intermediate connector for damage, and repair or replace as required. Refer to GROUP 00E, Harness Connector Inspection . If intermediate connector is in good condition, repair harness wire between MFI relay connector A-30X (terminal No. 2) and evaporative emission purge solenoid connector B-115 (terminal No. 2) because of open circuit or short circuit to ground. Then go to Step 10.

	Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 10.

	Go to Step 7.

	Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 10.

(1)Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors. (2)Turn the ignition switch to the "ON" position.

(3)Measure the voltage between terminal No. 37 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? Go to Step 8. Repair harness wire between evaporative emission purge solenoid connector B-115 (terminal No. 1) and ECM connector B-108 (terminal No. 37) because of open circuit or short circuit to ground. Then go to Step 10.

note Check harness connector after checking intermediate connector A-10. If intermediate connector is damaged, repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 10.

	Go to Step 9.

	Repair it. Then go to Step 10.

	Replace the ECM. When the ECM is replaced, register the ID code. Refer to GROUP 42B, Diagnosis - ID Code Registration Judgment Table <Vehicles with KOS> or GROUP 42C, Diagnosis - ID Codes Registration Judgment Table <Vehicles with WCM> . Then go to Step 10.

	Repair it. Then go to Step 10.

(1)Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .

	Retry the troubleshooting.

	The inspection is complete.