Магистраль или фитинг альтернативного топлива пропускает

A leak in the lines or fittings of a gaseous fuel system. It is a safety matter before it is a diagnostic one: liquefied petroleum gas is heavier than air and collects in pits, garages and low points rather than dispersing, so a leak accumulates exactly where somebody would work on the vehicle.

The system's own monitoring detects it as pressure that will not hold, and the module will typically close the tank valve and switch to petrol where the vehicle has that option — so the driver's complaint may be nothing more than the system no longer running on gas.

Detection uses a gas detector or an approved leak solution, never a flame and never smell alone — the odourant is a warning, not a measurement. These systems hold pressure far above a petrol system, so depressurise by the correct procedure before opening any joint. Most installations are aftermarket, so the routing follows nobody's factory diagram; trace the actual pipework, and treat the installer's documentation and the system's inspection record as the reference. Fittings disturbed at a previous service are the commonest leak point.