Purge control valve stuck closed, clogged or electrically faulty; Blocked, kinked, pinched or disconnected purge line or vapour hose between canister, valve and intake; Wiring or connector fault at the purge valve (open circuit, corrosion, poor connection); Saturated or blocked charcoal canister, often from overfilling the tank; Faulty or blocked vent valve, or restricted canister vent path, on systems that use one; Faulty fuel tank pressure sensor giving a wrong reading; Control unit fault or driver circuit failure.

P0497

EVAP System Low Purge Flow.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
97: FaultThe specific fault in that area

What it means

P0497 means the evaporative emission (EVAP) system has detected less purge flow than expected. During a purge test the control unit opens the purge valve and expects to see a pressure or fuel trim change in the system. When the change is too small, it concludes that vapour is not flowing properly from the charcoal canister to the engine intake and sets the code.

Symptoms

Malfunction indicator lamp on
Difficulty refuelling, with the pump clicking off repeatedly
Slight fuel smell around the car or fuel filler
Rough idle or hesitation after refuelling on some vehicles
Failed emissions test
No noticeable symptoms in many cases

Possible causes

Purge control valve stuck closed, clogged or electrically faultylikely
Blocked, kinked, pinched or disconnected purge line or vapour hose between canister, valve and intakelikely
Wiring or connector fault at the purge valve (open circuit, corrosion, poor connection)possible
Saturated or blocked charcoal canister, often from overfilling the tankpossible
Faulty or blocked vent valve, or restricted canister vent path, on systems that use onepossible
Faulty fuel tank pressure sensor giving a wrong readingrare
Control unit fault or driver circuit failurerare

How to diagnose

Read all stored and pending codes and review the freeze frame data for conditions when the fault set, noting any other EVAP codes.
Ask about recent refuelling habits, such as topping up after the pump clicks off, as this can saturate the canister.
Visually inspect the purge valve, its connector and wiring, and all vapour hoses for splits, kinks, blockage, disconnection or rodent damage.
Check the fuel filler cap seal and fit, as it can affect test results, though it is not the usual cause of low purge flow.
Command the purge valve on and off with a scan tool and listen for clicking; check that the valve changes state and that the fuel trims or tank pressure respond.
Measure the purge valve coil resistance and check the supply and control signals against the manufacturer's specification for that model.
With the engine off, check that the valve holds and then flows when energised, and blow through or apply vacuum following the correct procedure, to confirm it is not blocked.
Inspect the canister and vent valve for blockage or contamination, and check the tank pressure sensor reading against expected values; the exact layout varies by model.

How to fix

Replace the purge control valve if it is stuck, blocked or out of specification.
Clear, reroute or replace blocked, kinked or damaged vapour hoses and lines.
Repair wiring or connector faults, then confirm correct supply and control signals.
Replace the charcoal canister if it is saturated, contaminated or blocked, and advise against overfilling the tank.
Replace a faulty vent valve or tank pressure sensor if testing shows it is at fault.
After repair, clear the code and complete a drive cycle to confirm the EVAP monitor runs and passes.

Can I keep driving?

Low severity

The car is normally safe to drive and you can book it in for repair at your convenience. Do not ignore it for long, as a fuel smell, refuelling problems or a failed emissions test may follow.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.