FixItFor.Us
P codepowertrainLow severity

P218AFuel Level Sensor "A" Stuck

The primary fuel level sensor reading is not changing the way it should as fuel is consumed or added, indicating a stuck float or sender.

Definition

The PCM cross-checks the fuel level sensor against calculated fuel consumption from injector data and against expected changes after refueling. P218A sets when the reported level stays fixed while enough fuel has been burned or added that it must have changed. Beyond an inaccurate fuel gauge and possible unexpected run-out, a stuck level input disables EVAP leak monitors that depend on fuel level, so the EVAP readiness monitor may never complete and the vehicle can fail an inspection; the MIL may illuminate.

Common causes

  • Fuel level sender float arm stuck or binding in the tank
  • Worn or contaminated resistor card on the sender (sulfur deposits are common)
  • Fuel level float saturated or damaged
  • High resistance in sender wiring or connector
  • Deformed tank or debris obstructing float travel

Common misdiagnoses

  • Fuel pump module replaced when only the level sender is faulty
  • Instrument cluster replaced for a sender-side fault
  • EVAP components replaced chasing monitors that will not run
  • PCM replaced for a mechanical float problem

Troubleshooting steps

  1. 1.Watch the fuel level PID while adding fuel

    Add several gallons and confirm the PID rises; no change confirms a stuck sender or dead circuit rather than a rationality quirk.

  2. 2.Compare gauge, PID, and known fill level

    A gauge and PID frozen at the same value points at the sender; disagreement between them points at wiring or the cluster/BCM path.

  3. 3.Measure sender resistance sweep

    At the tank connector, resistance should change smoothly across the float's travel (typical spans are roughly 40-250 ohms, vehicle-specific); dead spots or a fixed value condemn the sender.

  4. 4.Inspect wiring and connectors to the tank

    Check the tank-top connector and chassis harness for corrosion and verify low voltage drop on signal and ground.

  5. 5.Remove the sending unit and inspect

    Look for a binding float arm, worn wiper contact, or tank deformation; try additive-resistant replacement cards where sulfur wear is known.

Related codes