P01B2 Alternative Fuel Tank A Level Sensor Circuit High

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. P01B2 means the signal voltage is above its upper limit – typically an open circuit or a short to voltage.

Likely causes

Symptoms

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

Repair estimate

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

Parts involved

Related codes

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