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P0463Fuel Level Sensor "A" Circuit High

The fuel level sensor signal is stuck above its normal range, typically pegging the gauge at full (or empty) no matter how much fuel is in the tank.

Definition

The PCM sets P0463 when the fuel level input exceeds the maximum plausible value — most often an open circuit (which pulls a biased signal to reference voltage) or a short to voltage in the sender circuit. The gauge typically pegs full or empty depending on the system's resistance mapping, the low-fuel warning becomes unreliable, and the driver can run out of fuel with the gauge still showing plenty. The MIL illuminates and the EVAP monitor may be suspended because the PCM cannot verify a valid tank level for leak testing.

Common causes

  • Open circuit in the sender signal wire or connector (most common)
  • Failed sender with a burned-through or worn-open resistor card
  • Broken wiper contact inside the fuel pump module
  • Signal wire shorted to a voltage source
  • Poor sender ground raising the signal voltage
  • Faulty cluster or PCM input (rare)

Common misdiagnoses

  • Fuel pump assembly replaced when a top-of-tank connector terminal was simply backed out
  • Instrument cluster replaced without testing the sender circuit
  • Gauge recalibration attempted when the input circuit is open
  • PCM replaced for a wiring fault it correctly flagged

Troubleshooting steps

  1. 1.Observe the fuel level PID against actual tank contents

    A PID pegged at 100% (or the signal voltage near 5 V reference) with a partially filled tank confirms a circuit-high fault.

  2. 2.Jumper the sender signal to ground at the tank connector

    With key on, grounding the signal should swing the PID/gauge to the opposite extreme; if it does, the harness and receiver are good and the sender is at fault.

  3. 3.Measure the sender resistance

    An OL reading across the sender terminals at any float position confirms an open resistor card or wiper.

  4. 4.Check circuit continuity and the sender ground

    Verify continuity of signal and ground wires end to end, and confirm less than 0.1 V of ground-side voltage drop with the circuit loaded.

  5. 5.Inspect the top-of-tank connector

    Look for backed-out, corroded, or heat-damaged terminals — a frequent cause after previous fuel pump service.

  6. 6.Repair, clear, and confirm

    Verify the gauge reads correctly at the known level and after refueling, and that P0463 does not return over multiple key cycles.

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