What it means
EVAP purge flow sensor above upper plausibility — open signal or short to B+. The evaporative system captures fuel vapor from the tank and purges it into intake; leaks or stuck purge valves leak hydrocarbons and cause emissions failures.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP purge flow sensor measures vapor moving from the charcoal canister into the engine during purge. P0468 sets when the control module sees a signal above its expected range, which can happen with an open signal wire or a short to battery voltage.
Common causes
Most likely first.
- Open signal line
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
How to diagnose it
- Review freeze-frame and live EVAP data to confirm the purge flow sensor signal was high when P0468 set.
- Inspect the sensor connector for loose or corroded terminals, water intrusion, and pins that have backed out.
- Trace the signal and supply wiring for breaks, pinching, or contact with a battery-voltage source.
- Using the vehicle wiring diagram, test for an open signal line or short to battery voltage and verify the sensor's supply and ground as applicable.
- If wiring is intact, test the purge flow sensor output against the manufacturer's specification.
Common fixes
- Reconnect or clean a loose or corroded purge flow sensor connector.
- Repair an open signal wire or insulation damaged where wiring contacts a power source.
- Repair damaged connector terminals.
- Replace the purge flow sensor if its output remains high with a verified circuit.
Can I keep driving?
You can generally drive if the vehicle runs normally, but the EVAP system may not purge fuel vapors correctly and the vehicle may fail an emissions inspection. Arrange diagnosis soon, and investigate promptly if fuel odor or drivability problems occur.
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.