P0466

P0466 is the range/performance variant of P0465 — the purge flow sensor signal is in range electrically but doesn't track plausibly against commanded purge duty cycle. The ECM commands the purge solenoid to open at X% duty and expects the flow sensor to report a corresponding mass flow within Y g/sec tolerance; when actual flow lags, leads, or stays flat relative to commanded duty across multiple drive cycles, P0466 sets. Cheapest-first ladder: (1) Datalog purge solenoid duty cycle alongside purge flow sensor voltage during a 15-minute warm drive — they should track linearly, with flow rising 0.5-4.5V across the 0-100 g/sec scale as duty climbs from 0-80%. (2) If flow stays at baseline (~0.5V) while duty cycle commands 50%+, the purge solenoid is stuck closed, the line is plugged with canister carbon dust, OR the flow sensor is reading low. Swap test: command purge OFF and squeeze the purge line by hand — you should hear/feel vapor pressure release. (3) If flow spikes to 4.0V+ instantly when purge commands 20%, the sensor is reading high or the line has a leak letting unmetered air in. (4) Remove the sensor and inspect the hot-wire/element for carbon fouling. Before condemning the purge flow sensor, verify the carbon canister itself isn't saturated with liquid fuel from repeated overfill — saturated canisters dump liquid into the purge line and flood the sensor, which mimics a sensor fault but is actually a tank-vent valve or fuel cap issue ($25 fuel cap fix vs. $400 sensor + canister).

Vehicle-specific patterns: 2007-2014 Volvo S60/S80/V70/XC90 throws P0466 from the same MAF-routing issue as P0465 — purge mass is measured both at the dedicated sensor and inferred at the MAF, and divergence between the two sets P0466. 2011-2017 Hyundai Sonata/Elantra/Tucson GDI throws P0466 when the carbon canister saturates and pushes liquid fuel through the purge line; the fix is a new canister plus a check of the tank vent valve operation. 2012-2018 Kia Optima/Forte GDI shares the Hyundai pattern. 2010-2015 Chevy Cruze 1.4L turbo throws P0466 from a leaking purge solenoid sealing diaphragm letting unmetered air past the sensor. Estimated repair: $180 to $550.