P0461

P0461 sets when the PCM sees fuel level sensor readings that change implausibly slowly, jump erratically, or fail to track fuel consumption inferred from injector pulse width over a drive cycle. Cheapest-first ladder: pull live data and watch the fuel level PID (volts or percent) while you add a known quantity of fuel. A healthy sender sweeps smoothly from roughly 0.2 to 4.5 volts (or 0 to 250 ohms on resistive senders) as the tank fills. Flat-lining at one value, stair-stepping, or dead spots in the middle of the sweep point to a worn rheostat card inside the sending unit. Before dropping the tank, wiggle-test the connector on top of the pump module and check ground continuity to chassis (under 0.1 ohm). Expensive misdiagnosis: replacing the entire fuel pump assembly when only the level sender card is bad, or chasing EVAP codes that share the same module connector.

Vehicle-specific patterns: 2008-2016 Chrysler Town & Country and Dodge Grand Caravan with the saddle-style tank use a transfer pump and two float arms tied together; the primary float pivot wears a flat into the resistor card around the 3/8-tank position, causing the gauge to stick and P0461 to set after a long highway run. 2007-2013 Chevrolet Silverado and GMC Sierra 1500 with the 5.3L commonly fail the sender card from sulfur-fouled contacts, fixed by AC Delco SK1422 sender alone rather than the full module. 2004-2010 Ford F-150 with the in-tank module sees the float arm bind on the bucket housing after pump replacement using off-brand kits. 2005-2012 Nissan Frontier and Xterra have a TSB for the level sensor harness chafing on the frame rail just forward of the tank strap. Estimated repair: $180 to $720.