[Previous][Next]
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.
  • 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 22 .
 
 
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:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), check actuator test item 10: Evaporative Emission Ventilation Solenoid.
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Turn the ignition switch to the "ON" position.
(3) 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.
(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 the evaporative emission ventilation solenoid.
(1) Disconnect connector, and measure at solenoid side.
(2) Measure the resistance between evaporative emission ventilation solenoid side connector terminals.
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 3.
Replace the evaporative emission ventilation solenoid. Then go to Step 8.
 
STEP 3. Measure the power supply voltage at evaporative emission ventilation solenoid harness side connector.
(1) Disconnect the evaporative emission ventilation solenoid connector and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal power supply line 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 4.
Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in power supply line between MFI relay connector and evaporative emission ventilation solenoid connector. Then go to Step 8.
 
STEP 4. Measure the power supply voltage at ECM connector.
(1) Disconnect connector, and measure at harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal P/VT 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 5.
Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in P/VT line between evaporative emission ventilation solenoid connector and ECM connector. Then go to Step 8.
 
STEP 5. Check of harness damage in P/VT line between evaporative emission ventilation solenoid connector and ECM connector.
Is the harness wire in good condition?
Go to Step 6.
Repair the connector(s) or wiring harness. Then go to Step 8.
 
STEP 6. Check of harness damage in power supply line between MFI relay connector and evaporative emission ventilation solenoid connector.
Is the harness wire in good condition?
Go to Step 7.
Repair the connector(s) or wiring harness. Then go to Step 8.
 
STEP 7. Using scan tool (M.U.T.-III), check actuator test item 10: 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 8.
 
STEP 8. 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 22 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0498 set?
Retry the troubleshooting.
The inspection is complete.