What it means
The EVAP purge pump does not produce the expected flow during purge cycles. Pump aging, restricted line, or canister loaded.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP purge pump moves fuel vapour from the charcoal canister toward the engine so it can be burned instead of escaping. The engine control module evaluates purge flow during commanded purge cycles and sets P2DFD when pump performance does not produce the expected flow. A restricted line or a canister loaded with fuel vapour can make a functioning pump appear weak.
Common causes
Most likely first.
- Pump output degraded
- Canister saturated with hydrocarbons
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
How to diagnose it
- Use freeze-frame data and scan-tool live data to confirm when purge was commanded and whether the reported EVAP flow or pressure response was low.
- Check that the fuel cap is fitted correctly and inspect the cap seal and filler area for damage, since a sealing problem can accompany EVAP warnings.
- Inspect accessible purge hoses and wiring for kinks, disconnections, cracks, heat damage, or loose pump and canister connectors.
- With a scan tool, command the purge pump using the vehicle's supported test and compare its response with the manufacturer's specification.
- If pump operation is present but flow remains low, test the line for restriction and assess the charcoal canister for saturation using the manufacturer's procedure.
Common fixes
- Refit or replace a damaged fuel cap or seal if it does not close securely.
- Reconnect or replace a cracked, kinked, or disconnected EVAP hose.
- Repair damaged wiring or a loose, corroded pump connector.
- Replace the purge pump if its output fails the manufacturer's test.
- Replace a saturated canister after confirming it is the cause of restricted purge flow.
Can I keep driving?
The vehicle is usually driveable if it runs normally, but fuel vapour may escape and the fault can cause an emissions inspection failure. Avoid driving if there is a strong fuel smell or any visible fuel leak, and have the EVAP fault repaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.