Powertrain, generic · Fuel and air metering

P01B3 Alternative Fuel Tank A Level Sensor Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

These codes only apply to vehicles with a gaseous alternative fuel – compressed natural gas (CNG) or LPG – as bi-fuel models alongside petrol or as dedicated gas engines; on bi-fuel vehicles a fault usually blocks gas operation and the vehicle runs on petrol. Tank level sensor A only exists where there is a real sender – typically LPG tanks with a float whose position is transmitted magnetically through the tank wall (Roush propane systems: 0.1–4.9 V). With CNG the 'level' is a calculated value. The documented systems report level faults under the petrol fuel level codes (Roush propane P0460–P0463, GM CNG van P0463), so no manufacturer document using exactly this code was found. P01B3 covers brief dropouts or jumps in the level signal – typically a loose contact or chafed wiring.

Likely causes

Loose contact or corrosion at the connector
Harness chafed along the gas line or underbody
Sensor unstable internally

Symptoms

  • Check engine light on
  • Gas level display wrong, jumping or empty
  • Range or refuelling information unreliable

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

alternative fuel tank level sensorsensor wiring

Related codes

P01AFP01B0P01B1P01B2P0464

References: law.cornell.edu, roushcleantech.com, eur-lex.europa.eu, static.nhtsa.gov.