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DTC P0498: Evaporative Emission Control System Ventilation Control Valve Circuit Low Input

 
 
 
 
CIRCUIT OPERATION
  • The evaporative emission ventilation solenoid power is supplied from the MFI relay (terminal No. 2).
  • The ECM controls ground evaporative emission ventilation solenoid by turning the power transistor in the ECM "ON" and "OFF".
 
 
TECHNICAL DESCRIPTION
  • In response to a signal from the ECM, the evaporative emission ventilation solenoid valve controls the flow rate of the ventilation air to be introduced into the intake manifold.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • The ECM detects open circuit and short malfunction.
 
 
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
Check Conditions
  • Engine is running.
  • Battery positive voltage is between 10 and 16.5 volts.
Judgment Criterion
  • The supply voltage is less than 3 volts without the evaporative emission ventilation solenoid driving for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
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 ventilation solenoid failed.
  • Open or shorted evaporative emission ventilation 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
    • MB991910: Main Harness A
  • MB992110: Power Plant ECU Check Harness
STEP 1. Using scan tool MB991958, check actuator test item 15: Evaporative Emission Ventilation Solenoid.
cautionTo 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 15, 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.
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 to Cope with Intermittent Malfunctions .
Go to Step 2.
 
STEP 2. Check harness connector D-44 at evaporative emission ventilation solenoid for damage.
Is the harness connector in good condition?
Go to Step 3.
Repair or replace it. Refer to GROUP 00E, 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-44.
(2) Measure the resistance between evaporative emission ventilation solenoid side connector terminal No. 1 and No. 2.
Standard value: 17 - 21 Ω [at 20°C (68°F)]
Is the measured resistance between 17 and 21 Ω [at 20°C (68°F)]?
Go to Step 4.
Replace the evaporative emission ventilation solenoid. Then go to Step 12.
 
STEP 4. Measure the power supply voltage at evaporative emission ventilation solenoid harness side connector D-44.
(1) Disconnect the connector D-44 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.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check harness connector A-37X at MFI relay for damage.
Is the harness connector in good condition?
Check harness connectors C-28 and D-21 at intermediate connectors for damage, and repair or replace as required. Refer to GROUP 00E, Harness Connector Inspection . If intermediate connectors are in good condition, repair harness wire between MFI relay connector A-37X (terminal No. 2) and evaporative emission ventilation solenoid connector D-44 (terminal No. 2) because of open circuit or short circuit to ground. Then go to Step 12.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.
 
STEP 6. Check harness connector B-27 at ECM for damage.
Is the harness connector in good condition?
Go to Step 7.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.
 
STEP 7.Measure the power supply voltage at ECM connector B-27 by using power plant ECU check harness special tool MB992110.
(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. 117 and ground.
  • Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 8.
Check harness connectors C-28 and D-21 at intermediate connector for damage, and repair or replace as required. Refer to GROUP 00E, Harness Connector Inspection . If intermediate connectors are in good condition, repair harness wire between evaporative emission ventilation solenoid connector D-44 (terminal No. 1) and ECM connector B-27 (terminal No. 117) because of open circuit or short circuit to ground. Then go to Step 12.
 
STEP 8. Check harness connector A-37X at MFI relay for damage.
Is the harness connector in good condition?
Go to Step 9.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.
 
STEP 9. Check for harness damage between evaporative emission ventilation solenoid connector D-44 (terminal No. 1) and ECM connector B-27 (terminal No. 117).
noteCheck harness after checking intermediate connectors C-28 and D-21. If intermediate connectors are damaged, repair or replace them. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12
Is the harness wire in good condition?
Go to Step 10.
Repair the connector(s) or wiring harness. Then go to Step 12.
 
STEP 10. Check for harness damage between MFI relay connector A-37X (terminal No. 2) and evaporative emission ventilation solenoid connector D-44 (terminal No. 2).
noteCheck harness after checking intermediate connectors C-28 and D-21. If intermediate connectors are damaged, repair or replace them. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12
Is the harness wire in good condition?
Go to Step 11.
Repair the connector(s) or wiring harness. Then go to Step 12.
 
STEP 11. Using scan tool MB991958, check actuator test item 15: Evaporative Emission Ventilation Solenoid.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool (M.U.T.-III) to the actuator test mode for item 15, Evaporative Emission Ventilation Solenoid.
  • An operation sound should be heard and vibration should be felt when the evaporative emission ventilation solenoid is operated.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
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 to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to Removal and Installation ).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 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0498 set?
Retry the troubleshooting.
The inspection is complete.