Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0499
DTC P0499:Â Evaporative Emission (EVAP) Canister Vent Shut Valve Circuit High Voltage
General DescriptionÂ
The evaporative emission (EVAP) canister vent shut valve is attached to the EVAP canister to control the venting of the EVAP canister to atmosphere. The EVAP canister vent shut valve is open (open to atmosphere) when the VSV signal is OFF. If the return signal is "ON" when the powertrain control module (PCM) outputs the "OFF" signal to the EVAP canister vent shut valve, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC TypeÂ
| Execution | Continuous |
| Sequence | None |
| Duration | 5 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable ConditionsÂ
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [BATTERY] | 10.0 V | - |
| State of the engine | Running | |
[ ]: HDS Parameter
Malfunction ThresholdÂ
The return signal is "ON" for at least 5 seconds when the PCM outputs the "OFF" signal to the EVAP canister vent shut valve.
Possible CauseÂ
NOTE:Â The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- EVAP canister vent shut valve failure
- EVAP canister vent shut valve VSV line short to power
- PCM internal circuit failure
Confirmation ProcedureÂ
Operating ConditionÂ
Start the engine.
With the HDSÂ
Select EVAP TEST in the INSPECTION MENU, and do the EVAP CVS ON in the SINGLE SOLENOID with the HDS.
Diagnosis DetailsÂ
Conditions for setting the DTCÂ
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTCÂ
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.