Faulty alternative fuel tank level sensor or sender unit; Damaged wiring, corrosion or poor connections in the level sensor circuit (open circuit, short or high resistance); Sensor ground or reference supply fault; Sensor reading affected by physical fault in the tank, such as a stuck float or a damaged or contaminated sender; Fuel system control module fault or outdated software, where the manufacturer lists it as a known cause; Incorrect sensor fitted after conversion or repair, or a poorly matched sensor calibration.

P01B0

Alternative Fuel Tank A Level Sensor Range/Performance.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
B0: FaultThe specific fault in that area

What it means

P01B0 means the control unit has judged the signal from the alternative fuel tank A level sensor to be implausible or out of its expected range. This is usually on a vehicle running LPG, CNG or another secondary fuel. The reading may not match fuel use, may not change as expected, or may stay fixed while fuel is being used or added. The exact plausibility test depends on the vehicle and fuel system.

Symptoms

Alternative fuel gauge reads wrongly, jumps about or sticks at one level
Engine warning light on
Unexpected switch back to petrol or the primary fuel
Alternative fuel mode unavailable or limited
Poor range estimates or false low-fuel warnings for the alternative fuel

Possible causes

Faulty alternative fuel tank level sensor or sender unitlikely
Damaged wiring, corrosion or poor connections in the level sensor circuit (open circuit, short or high resistance)likely
Sensor ground or reference supply faultpossible
Sensor reading affected by physical fault in the tank, such as a stuck float or a damaged or contaminated senderpossible
Fuel system control module fault or outdated software, where the manufacturer lists it as a known causerare
Incorrect sensor fitted after conversion or repair, or a poorly matched sensor calibrationrare

How to diagnose

Read all stored and pending codes and the freeze frame data, and note any related alternative fuel, fuel level or supply voltage codes.
Compare the displayed alternative fuel level with the actual amount of fuel in the tank, using a known fill state if possible.
Inspect the level sensor wiring, connectors and any tank-mounted multiplug for damage, water, corrosion, chafing or loose pins.
With live data, watch the level sensor value while the fuel level changes, and check that it moves smoothly and plausibly without jumps or freezing.
Check the sensor supply, signal and ground at the connector against the manufacturer's specification, and test for open circuits or shorts in the wiring.
Test the sensor itself against the specified resistance or voltage range, following the correct safe procedure for the alternative fuel system.
Check for relevant technical bulletins or software updates for the vehicle and conversion system, as procedures vary by model and system.
Clear the code after repair and road test to confirm it does not return.

How to fix

Repair or replace damaged wiring, terminals or connectors in the level sensor circuit.
Replace the alternative fuel tank level sensor or sender unit if it is out of specification or sticking.
Restore a good ground and supply to the sensor if either is faulty.
Correct any fitting or compatibility problem with the sensor or conversion components.
Update or replace the control module only if testing confirms a fault or a known software issue.

Can I keep driving?

Low severity

The car can usually be driven, normally on the primary fuel, but book it in soon. Any work on LPG or CNG components should be done by someone qualified to handle them, and you should stop and seek help if you smell gas.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.