P0463

P0463 means the fuel level signal voltage has stayed above the PCM's high threshold, typically over 4.6 to 4.9 volts, longer than the diagnostic window allows. This is usually a signal wire open, a failed sender stuck at full, or loss of sender ground. Cheapest-first: with key on, back-probe the signal pin at the sender connector. A reading at or near 5.0 volts (reference voltage with no load) confirms the sender circuit is open between the connector and the resistive element, either a broken pigtail, a corroded pump-flange pass-through, or a snapped float arm. If signal voltage is normal at the tank but the scan tool reads 5.0 volts, the wire is open between the tank and the PCM. Always verify the sender ground reads under 0.2 volts drop to battery negative with the key on; a lost ground floats the signal high and mimics an open sender. Expensive misdiagnosis: replacing the fuel pump module twice when the actual fault is a broken solder joint at the tank-top connector pin or a corroded ground eyelet on the frame rail.

Vehicle-specific patterns: 2002-2008 Dodge Ram 1500 and 2500 with the in-tank module crack the signal pin solder joint at the flange where the harness flexes during fuel sloshing, throwing P0463 on left turns when the tank is below half. 2007-2013 GMC Sierra and Chevrolet Silverado 1500 lose the sender ground at the C305 body connector under the driver seat after winter salt exposure. 2005-2011 Ford Escape and Mercury Mariner break the float arm at its plastic pivot, especially after running the tank dry repeatedly. 1996-2002 Toyota 4Runner with the 5VZ-FE has a TSB for the tank-top connector terminal back-out causing intermittent P0463 over rough roads. Estimated repair: $140 to $620.