B0120 Lancia Y10 is described as Oxygen Sensor Circuit No Activity Detected (Bank 1, Sensor 1). This means there's a problem in the front oxygen sensor on Bank 1, as the O2 sensor is inactive. So if the problem persists despite of your diagnosis, then you should never hesitate to take your vehicle to your dealer or to a qualified mechanic.
Possible Causes :
Look at the plug wires to make sure they are not burnt or laying on the exhaust. Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.
Diagnostic trouble code B0120 Lancia Y10 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before B0120 Lancia Y10.
Fortunately, B0120 Lancia Y10 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.