Faulty EVAP purge solenoid valve that doesn't open (both sources). Defective EVAP pressure sensor (OBD-Codes.com; RepairPal lists fuel tank pressure sensor replacement as the common repair). Restricted EVAP charcoal canister (OBD-Codes.com). Open or shorted wiring or connector for the purge valve (both sources). Cracked, crimped or collapsed vacuum lines or hoses (OBD-Codes.com). Failed powertrain control module (PCM) or a PCM programming error, less likely (both sources).

Replace a purge solenoid valve that fails to open. Replace a failed EVAP or fuel tank pressure sensor (RepairPal's listed common repair). Replace a restricted charcoal canister. Repair or replace damaged vacuum lines, hoses, wiring or connectors. Check for technical service bulletins (TSBs) for your vehicle, as OBD-Codes.com recommends, then diagnose or reprogram the PCM only if everything else checks out.

P0497🔧 Evaporative emissions (EVAP)Usually OK to drive

P0497: EVAP System Low Purge Flow (Meaning, Causes, Fixes)

Q: What does P0497 mean?

P0497 means the engine computer expected fuel vapor to flow from the EVAP system into the engine and saw too little. The usual suspects are a purge solenoid valve that won't open, a bad EVAP pressure sensor, a restricted charcoal canister, or a cracked or collapsed hose. The evaporative emission (EVAP) system traps fuel vapor from the gas tank in a charcoal canister, then lets the engine burn it by opening a purge valve between the canister and the intake. OBD-Codes.com explains that the powertrain control module (PCM) usually opens the purge valve by grounding it when driving conditions are right, so intake vacuum pulls vapor out of the canister. Depending on the system, the PCM either looks for a change in manifold pressure or exhaust oxygen when the valve opens, or watches an EVAP pressure sensor for a pressure drop. If the expected change doesn't happen, it sets P0497. RepairPal describes it the same way: the PCM detects that the EVAP system is not purging when it should. It is a generic OBD-II code, and P0496 is the matching high purge flow code.

Q: Can I keep driving with P0497?

Usually OK to drive. Usually safe to drive in the short term, but get it fixed. RepairPal rates P0497 Moderate, meaning it may not threaten safety right away but should be diagnosed within a reasonable time. OBD-Codes.com calls it an emissions-related code with no inherent danger, though it may slightly reduce fuel economy. An EVAP fault that keeps the check engine light on can also make the car fail an emissions inspection.

Reviewed 2026-10-23 · Based on 2 cited source(s)

What P0497 means

The evaporative emission (EVAP) system traps fuel vapor from the gas tank in a charcoal canister, then lets the engine burn it by opening a purge valve between the canister and the intake. OBD-Codes.com explains that the powertrain control module (PCM) usually opens the purge valve by grounding it when driving conditions are right, so intake vacuum pulls vapor out of the canister. Depending on the system, the PCM either looks for a change in manifold pressure or exhaust oxygen when the valve opens, or watches an EVAP pressure sensor for a pressure drop. If the expected change doesn't happen, it sets P0497. RepairPal describes it the same way: the PCM detects that the EVAP system is not purging when it should. It is a generic OBD-II code, and P0496 is the matching high purge flow code.

Severity: can I keep driving?

Usually OK to drive

Usually safe to drive in the short term, but get it fixed. RepairPal rates P0497 Moderate, meaning it may not threaten safety right away but should be diagnosed within a reasonable time. OBD-Codes.com calls it an emissions-related code with no inherent danger, though it may slightly reduce fuel economy. An EVAP fault that keeps the check engine light on can also make the car fail an emissions inspection.

Common symptoms

Check engine light on (OBD-Codes.com says that in most cases there are no other symptoms)
Slightly lower fuel economy (OBD-Codes.com)
Sound of a vacuum leak under the hood (OBD-Codes.com)
Poor idle quality (OBD-Codes.com)
Decreased engine performance (RepairPal)
The sources differ on symptoms: OBD-Codes.com says most cars show none besides the light, while RepairPal lists decreased engine performance as its only symptom

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Faulty EVAP purge solenoid valve that doesn't open (both sources)
Defective EVAP pressure sensor (OBD-Codes.com; RepairPal lists fuel tank pressure sensor replacement as the common repair)
Restricted EVAP charcoal canister (OBD-Codes.com)
Open or shorted wiring or connector for the purge valve (both sources)
Cracked, crimped or collapsed vacuum lines or hoses (OBD-Codes.com)
Failed powertrain control module (PCM) or a PCM programming error, less likely (both sources)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Read all stored codes and the freeze frame data and write them down; other EVAP codes can point to the same part.
Look over the EVAP hoses, metal lines and wiring, especially the purge valve in the engine bay and the hoses running back toward the canister. Replace anything cracked, crimped, collapsed or damaged.
If you find black charcoal granules inside the hoses, OBD-Codes.com says to suspect the canister, which usually has to be replaced as a whole.
Clear the code and drive normally. OBD-Codes.com notes it can take several ignition cycles for this code to come back, so give it time before judging a repair.
A loose or missing gas cap will not cause P0497, according to OBD-Codes.com, so don't expect a new cap to fix it.
If the engine is running poorly for another reason, fix that first; OBD-Codes.com notes a poor-running engine may not make enough vacuum for the purge system to work.

Typical fixes

Replace a purge solenoid valve that fails to open
Replace a failed EVAP or fuel tank pressure sensor (RepairPal's listed common repair)
Replace a restricted charcoal canister
Repair or replace damaged vacuum lines, hoses, wiring or connectors
Check for technical service bulletins (TSBs) for your vehicle, as OBD-Codes.com recommends, then diagnose or reprogram the PCM only if everything else checks out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

Testing needs a scan tool that can command the purge valve open while you check for vacuum flow with the engine running, as OBD-Codes.com describes
Finding a leak or restriction in the long EVAP lines is much easier with a smoke machine
The purge valve, its voltage and ground all test good but the code keeps returning, which OBD-Codes.com says points toward the PCM
You have an emissions inspection coming up and need the EVAP monitor to complete

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0497 serious?

Not usually. RepairPal rates it Moderate, and OBD-Codes.com says it is an emissions code with no inherent danger, though fuel economy may drop slightly. Get it fixed in a reasonable time, especially before an emissions test.

What is the difference between P0496 and P0497?

P0496 means high purge flow, where vapor flows when it shouldn't, while P0497 means low purge flow, where the system isn't purging when it should. RepairPal lists both with these names.

Can a gas cap cause P0497?

No. OBD-Codes.com says a loose or missing fuel cap will not cause this code to be stored.

How much does it cost to fix P0497?

Neither source gives a repair cost. The price depends on whether the purge valve, a pressure sensor, the canister or a hose is at fault, so get a diagnosis or a written estimate before replacing parts.

Sources

Last reviewed 2026-10-23. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.