Evaporative Emission System Low Purge Flow
The P0497 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission System Low Purge Flow. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $300 (parts and labor)
A cracked or loose gas cap causes 60%+ of EVAP codes. This $8 replacement clears P0442, P0455, and P0457 more often than any other repair.
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If a new gas cap does not clear it, the leak is somewhere in the EVAP plumbing. A smoke machine finds the exact leak -- a cracked hose, bad seal, or stuck vent valve -- in minutes instead of guessing at parts.
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Clear the code after the repair. If the light stays off after 50 miles, you just saved $200+ in shop fees.
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Common Symptoms
- Check Engine Light on
- Failed emissions test
- No noticeable drivability symptoms
- Fuel vapor odor near vehicle
Probable Causes (Ranked by Likelihood)
- EVAP purge valve stuck closed or not opening fully Very High
- Blocked EVAP purge line between canister and intake High
- Faulty purge flow sensor Moderate
- Disconnected or kinked purge hose Moderate
Step-by-Step Diagnostic Procedure
-
Command the purge valve open with a scan tool and listen for a click; check for vacuum at the purge hose
-
Inspect the purge line from the canister to the intake for blockages, kinks, or disconnections
-
Apply 12V directly to the purge valve and verify it opens; no click or vacuum flow indicates a failed valve
-
Check the purge flow sensor for proper readings during commanded purge operation
Common Fixes by Vehicle
What techs usually find when diagnosing P0497 on specific vehicles — tap your vehicle for the fix and the exact part:
2006-2020 Honda Civic/Accord 1.5T/2.0L/2.4L easy DIY
P0497 indicates low EVAP purge flow. On Honda vehicles, the purge control solenoid valve (PCSV) is clogged or stuck closed. Located on the intake manifold, the PCSV can be tested by applying 12V -- you should hear a click and feel airflow. If it does not open, replace. Also check the EVAP hose from the canister to the purge valve for kinks or collapse.
Labor: 20-30 min2007-2020 Acura TL/TSX/RDX 2.4L/3.5L easy to moderate DIY
Acura uses the same EVAP system as Honda. P0497 is typically a failed purge solenoid or a collapsed EVAP hose between the charcoal canister and the intake. Inspect the rubber hoses for collapse (they soften with age and fuel vapor exposure). Replace both the purge solenoid and any soft hoses. Use Honda/Acura OE hoses for best fit.
Labor: 30-45 min2008-2020 Honda CR-V/Pilot 2.4L/3.5L moderate DIY
On larger Honda SUVs, P0497 can also be caused by a clogged charcoal canister (from overfilling the fuel tank or fuel getting into the canister). Check canister for fuel contamination. If the canister is saturated, it restricts purge flow. Replace the canister and the purge valve together. Avoid topping off fuel past the first click of the nozzle.
Labor: 1-2 hoursFrequently Asked Questions
Will P0497 cause any drivability issues?
P0497 typically does not cause noticeable drivability issues since it only affects how fuel vapors are purged from the charcoal canister. However, it will cause a failed emissions test and the Check Engine Light to illuminate.
What happens if fuel vapors are not purged?
If fuel vapors are not purged from the charcoal canister, the canister can become saturated over time. This can lead to fuel vapor odors near the vehicle and may eventually cause other EVAP system codes.
Is P0497 an expensive repair?
No. P0497 is usually one of the less expensive repairs. The most common fix is replacing the purge valve, which is a relatively inexpensive part and typically easy to access on most vehicles.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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