OBD Alternative Fuel Tank B Level Sensor Circuit Intermittent/Erratic
What it means
P2A63 stands for Alternative Fuel Tank B Level Sensor Circuit Intermittent/Erratic. P2A63 is a P code, so the fault sits in the engine, transmission and emissions systems. For P2A63, work through the cause list below, cheapest checks first.
Where it lives
For P2A63, the circuit described runs through the sensor. The description of P2A63 reports a fault at the sensor.
What to check first
For P2A63, check the wiring and connector on this circuit first, since a broken terminal gives the same reading as a failed part.
Check these first
- P2A63: Faulty or contaminated sensor in the fuel/air metering circuit
- P2A63: Damaged or shorted wiring or connector for the affected circuit
- P2A63: Vacuum leak or intake system restriction
- P2A63: Failing fuel pump, injector, or fuel pressure regulator
What to do next
P2A63 is a fault in the powertrain control system. The steps below are general, so what actually failed on your vehicle may not be what P2A63 names.
- P2A63: Read freeze frame data and related codes with an OBD-II scanner
- P2A63: Inspect the affected sensor wiring and connector for damage
- P2A63: Compare live sensor readings (fuel trim, airflow, temperatures) to manufacturer specs
- P2A63: Smoke test the intake system if lean or vacuum conditions are suspected
- P2A63: Replace the failed component after confirming it with live data
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Updated
Generic SAE J2012 definition. Last updated 2026-08-30.