LPG

📖 YOUCANIC Automotive Glossary

LPG (Liquefied Petroleum Gas), also called propane or autogas, is an alternative fuel stored as a liquid under moderate pressure (200-300 PSI) in dedicated tanks. LPG is popular for fleet vehicles, forklifts, and aftermarket conversions in markets with favorable LPG pricing. LPG burns cleaner than gasoline with lower CO2 and particulate emissions, though NOx can be similar. Most LPG vehicles are bi-fuel — they start on gasoline and switch to LPG once the engine is warm, with the ability to switch back to gasoline if the LPG tank is empty.

LPG conversion systems include a tank (often mounted in the spare tire well or under the vehicle), a vaporizer/regulator (converting liquid to gas), LPG injectors (parallel to gasoline injectors), and an LPG ECU that communicates with the OE engine ECU. Diagnostic considerations include the LPG system’s own DTCs (accessible through the LPG ECU), OE engine codes that may be triggered by the LPG system’s fuel delivery characteristics, and potential issues with fuel trim adaptation when switching between fuels.