Used Alfa Romeo 155 Oxygen Sensor

Yes, petrol-engined Alfa Romeo 155s are fitted with at least one lambda (oxygen) sensor, which sits in the exhaust system and feeds data to the engine management unit to regulate the fuel mixture. The 155 was produced from 1992 to 1998 and petrol variants across that range use this sensor as part of their closed-loop fuel management. Diesel variants of the 155 did not use an oxygen sensor in the same way, so if your car is a diesel, an oxygen sensor is not the part you need — confirm with a breaker what exhaust or engine management components apply to your diesel variant.

The 155 ran through a single generation from 1992 to 1998, with a facelift arriving around 1995 that brought some revised trim and interior updates, but the core engine codes carried across much of the range. Oxygen sensor compatibility is driven by the engine code rather than the production year or facelift status, so the key question is whether both cars share the same engine — if they do, the sensor is very likely to be the same unit. Ask your breaker to match the part against your specific engine code and registration rather than assuming year alone is a reliable guide.

No, trim level has no bearing on oxygen sensor fitment for the 155 — the sensor is determined entirely by the engine fitted to your car, not by whether you have a base, Twin Spark, or Q4 variant. The Q4 four-wheel-drive models used specific engines too, so again it is the engine code that matters. Give your breaker your engine code and they will be able to identify the correct sensor regardless of trim.

Yes, engine code is the most important factor — the 155 was offered with a range of four-cylinder and V6 petrol engines, and the sensor specification, thread size, connector type, and position in the exhaust can differ between them. Always quote your engine code to the breaker, which you can find on your V5C or by checking under the bonnet. Do not rely on engine displacement alone, as some capacities were offered in more than one state of tune with different management systems.

Probably not without verification — the Twin Spark name covers different engine displacements that, while sharing architecture, may use sensors with different connectors or calibration. The safest approach is to give the breaker both your exact engine code and your registration so they can cross-reference the correct part number rather than going on displacement or the Twin Spark badge alone. A sensor from an incompatible engine variant may fit physically but cause running problems or a failed emissions test, so it is worth taking a moment to confirm.

Some oxygen sensors from the early-to-mid 1990s were shared across Fiat Group vehicles — including Fiat and Lancia models using the same engine families — and universal aftermarket sensors do exist, but for a used part from a breaker you should still match by engine code and connector type rather than assuming cross-brand compatibility. A sensor from the wrong application may have an incompatible wiring plug, incorrect thread, or different output characteristics that upset the engine management. Ask the breaker to confirm the part against your engine code and registration before purchasing.