Fuel and air

P01B0 — Alternative Fuel Tank A Level Sensor Range/Performance

Severity: low Safe to drive

What P01B0 means

The control module sees a signal from the alternative fuel tank A level sensor that is outside the expected range or does not match actual fuel use. This tank is found on vehicles with CNG, propane or similar fuel systems. The module uses the sensor to calculate remaining fuel and driving range and to manage the fuel system.

Symptoms

  • Check Engine Light is on
  • Alternative fuel gauge reads erratically or incorrectly
  • Wrong driving range estimates
  • Fuel system warning messages on the dash
  • Early switchover to the primary fuel

Possible causes

  1. Faulty alternative fuel tank level sensor
  2. Open, shorted or corroded wiring or connector at the sensor
  3. Mechanical damage to the tank or sender unit
  4. Poor ground or reference voltage problem in the sensor circuit
  5. ECU/PCM fault (rare)

How to diagnose

  1. Scan the codes, record freeze frame data, then clear the code and see if it returns.
  2. Compare the scan tool fuel level reading with the actual amount of fuel in the tank.
  3. Inspect the sensor connector and harness for corrosion, chafing and moisture.
  4. Check reference voltage, ground and signal wires with a multimeter, following the factory wiring diagram.
  5. Measure the sensor resistance or output and compare it to specification.
  6. Inspect the tank and sender assembly for damage; have any work on the gas system done by a qualified shop.
  7. If wiring and sensor are good, check the control module and its software version.

Common fixes

  • Replace the alternative fuel tank A level sensor
  • Repair damaged wiring or replace the connector
  • Repair or replace a damaged tank or sender assembly
  • Update or replace the control module if confirmed faulty

Questions and answers

What does P01B0 mean?

It is a range/performance fault for the alternative fuel tank A level sensor. The control module sees a signal outside the expected limits.

Can I drive with P01B0?

Usually yes, but the fuel level reading may be wrong. Keep track of how much fuel is left and get it diagnosed soon.

How do I fix P01B0?

Start with the sensor wiring and connector, then test the sensor itself. The usual fix is a wiring repair or a new level sensor.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.