What it means
The control module checks whether the alternative fuel tank A level sensor reading is plausible as fuel level changes. It sets this code when the reading is outside the expected range or does not respond as expected.
At a glance
- Usually lights the check-engine light
How it works
The alternative fuel tank A level sensor reports how much fuel is in that tank to the control module. The module compares the reading with expected values and how it changes as the fuel level changes; it sets P01B0 when the reading is implausible or does not track those changes properly.
Common causes
Most likely first.
- Sensor reading drifted
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- Check-engine light on
- Alternative-fuel level reading may be inaccurate or fluctuate
- Fuel gauge or range estimate may be unreliable
How to diagnose it
- Record freeze-frame data and compare the tank A level reading with the displayed gauge and known fuel level to see when they disagree.
- Watch tank A level data on a scan tool while the vehicle is stationary, then during normal fuel-level changes, and look for a reading that sticks, drifts, or moves implausibly.
- Inspect the tank A sensor connector, wiring, and mounting for looseness, damage, or signs the sensor is not held securely.
- Check the tank A sensor signal and its wiring for stable changes as the level changes, following the manufacturer's test procedure.
- If the wiring and mounting are sound, test the tank A sensor against the manufacturer's specification and replace it if it has drifted out of range.
Common fixes
- Secure a loose tank A level sensor or its mounting.
- Repair damaged or loose tank A sensor wiring or connector.
- Replace the tank A level sensor if its reading is inaccurate or fails the manufacturer's test.
Can I keep driving?
The code mainly makes the alternative-fuel gauge and range estimate unreliable, so do not rely on them to judge how much fuel remains. Refuel conservatively and arrange diagnosis soon; the code alone does not indicate an immediate drivability problem.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.