What Does P0497 Mean?
The PCM has detected that the evaporative emission system purge flow is lower than expected when the purge valve is commanded open. The system is not purging sufficient fuel vapor from the charcoal canister to the intake manifold, which can cause the canister to become saturated with fuel vapor, leading to fuel odors, increased emissions, and potentially a swollen fuel tank.
Common Causes
40%
EVAP canister purge valve stuck closed or not opening fully due to carbon contamination or failed solenoid coil
25%
Blocked or kinked purge hose between canister and intake manifold restricting vapor flow
20%
Saturated or plugged charcoal canister with restricted internal flow due to excessive fuel exposure or age
15%
Open circuit in the purge valve control wiring preventing the PCM from energizing the solenoid
Diagnostic Steps
1
Command the purge valve open using a bidirectional scan tool at various duty cycles (25%, 50%, 100%). Listen for the solenoid clicking and monitor fuel trim changes. No change in fuel trims indicates no vapor is flowing.
2
Disconnect the purge hose at the intake manifold with the engine running and purge valve commanded open. Place your finger over the hose end to feel for vacuum. No vacuum indicates the purge valve is not opening.
3
With the purge valve removed, apply 12V and ground directly to the solenoid terminals and attempt to blow through the valve. It should be sealed when de-energized and open freely when powered.
4
Inspect the purge hose for kinks, collapse, or blockage by blowing compressed air through the entire path from purge valve to canister. Any restriction will reduce purge flow below the PCM's threshold.
5
If the purge valve and hoses are clear, suspect a saturated charcoal canister. Remove the canister and shake it; a saturated canister will sound and feel heavy with liquid fuel. Replace the canister if contaminated.
Estimated Repair Cost
$50 - $300
Parts + labor, varies by vehicle and location
The PCM has detected that the evaporative emission system purge flow is lower than expected when the purge valve is commanded open. The system is not purging sufficient fuel vapor from the charcoal canister to the intake manifold, which can cause the canister to become saturated with fuel vapor, lea...
The most common cause of P0497 (Evaporative Emission System Low Purge Flow) is: EVAP canister purge valve stuck closed or not opening fully due to carbon contamination or failed solenoid coil
Typical repair costs for P0497 range from $50 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Low purge flow causes the charcoal canister to remain saturated with fuel vapors, which may produce noticeable fuel odor around the vehicle. While not immediately hazardous, saturated canisters can cause fuel tank pressurization and increased hydrocarbon emissions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0497 to identify the root cause.
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Quick Info
Category
Powertrain
System
Evaporative Emission Control System (EVAP)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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