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P0462Fuel Level Sensor "A" Circuit Low

The fuel level sensor signal is stuck below its normal range, usually making the gauge read empty and turning on the low-fuel light regardless of actual fuel.

Definition

The PCM monitors the fuel level sender voltage and sets P0462 when the signal drops below the minimum plausible threshold — typically a short to ground in the signal wire or a sender resistance that has fallen out of range. Depending on the gauge design, the cluster reads empty (or full, on some resistance-inverted systems) no matter how much fuel is in the tank. The MIL illuminates, the driver loses accurate range information and can run out of fuel, and the PCM may block the EVAP monitor because it can't confirm a valid fuel level.

Common causes

  • Fuel level signal wire chafed and shorted to ground
  • Failed sender with wiper shorted at one end of the resistor card
  • Corrosion or fuel intrusion inside the fuel pump module connector
  • Damaged flex circuit or connections inside the pump module
  • Sunk float holding the wiper at the empty stop
  • Faulty cluster or PCM input circuit pulling the signal low (rare)

Common misdiagnoses

  • Fuel pump replaced when only the level sender or wiring is shorted
  • Instrument cluster replaced without checking the sender circuit
  • Low-fuel warning module/lamp chased when the input signal itself is low
  • Battery/charging issues blamed for a gauge that is pegged by a circuit short

Troubleshooting steps

  1. 1.Read the fuel level PID and note the raw value

    A PID pegged at 0% (or the voltage PID at near 0 V) regardless of tank contents confirms a circuit-low condition rather than a gauge fault.

  2. 2.Unplug the tank module and observe the change

    With the sender disconnected, the signal should swing to the opposite extreme (open-circuit reading); if it stays low, the harness is shorted to ground.

  3. 3.Measure the sender resistance at the module connector

    Compare to spec for the actual fuel level; a near-zero reading with fuel in the tank condemns the sender.

  4. 4.Check the signal wire for a short to ground

    With both ends disconnected, resistance from the signal wire to chassis ground should be OL; inspect where the harness passes over the tank and frame.

  5. 5.Repair or replace the failed component

    Replace the sender (or pump module) or repair the harness short, protecting the repair with proper loom where it chafed.

  6. 6.Verify gauge accuracy after repair

    Confirm the gauge and PID track correctly at the current level and after adding fuel, and that the code stays clear.

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