Volt

DTC P0449, P0498, or P0499

The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. Battery voltage is supplied to the normally closed evaporative emission (EVAP) vent solenoid valve. The ECM grounds the EVAP vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

DTCs P0449, P0498 and P0499 run continuously when the above conditions are met.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 5 s.

DTCs P0449, P0498 and P0499 are Type B DTCs.

DTCs P0449, P0498 and P0499 are Type B DTCs.

Where multiple DTCs set look for a common root cause like battery feeds, grounds, splices, etc.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Evaporative Emission Control System Description

Hybrid Modes of Operation Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle in Service Mode, command the EVAP vent solenoid valve ON and OFF with a scan tool. Listen for a click when the valve operates.
2. Vehicle in Service Mode, observe the EVAP vent solenoid output control parameters with a scan tool.

•	EVAP Vent Solenoid Valve Output Circuit High Voltage Test Status

•	EVAP Vent Solenoid Valve Output Circuit Open Test Status

•	EVAP Vent Solenoid Valve Output Circuit Low Voltage Test Status

Each parameter should display OK or Not Run.

3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Vehicle OFF, disconnect the harness connector at the Q13 evaporative emission vent solenoid valve.
2. Vehicle in Service Mode, verify that a test lamp illuminates between the battery voltage circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the battery voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the battery voltage circuit fuse is open, test all components connected to the battery voltage circuit and replace as necessary.

3. Test for 2.5-3.5 V between the control circuit terminal 1 and ground.

⇒	If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the K20 engine control module.

⇒	If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.

4. Command the EVAP vent solenoid valve On and Off with a scan tool. The DMM should transition from 2.5-3.5 V when commanded Off, to less than 0.2 V when commanded On..

⇒	If the circuit voltage does not correspond to the specified values, replace the K20 engine control module.

5. If all circuits test normal, test or replace the Q13 evaporative emission vent solenoid valve.

1. Vehicle OFF, disconnect the harness connector at the Q13 evaporative emission vent solenoid valve.
2. Test for 25.0-30.0 Ω between the control terminal 1 and the battery voltage terminal 2.

⇒	If not within the specified range, replace the Q13 evaporative emission vent solenoid valve.

3. Test for no air flow through the Q13 evaporative emission vent solenoid valve by applying vacuum to the pump side of the valve. It should hold 1-2 in. Hg (3-7 kPa) for 30 s.

⇒	If not within the specified range, replace the Q13 evaporative emission vent solenoid valve.

4. Reconnect the harness connector at the Q13 evaporative emission vent solenoid valve.
5. Command the Q13 evaporative emission vent solenoid valve On with a scan tool and apply vacuum to the pump side of the valve. It should not hold vacuum.

⇒	If not within the specified range, replace the Q13 evaporative emission vent solenoid valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.