P0173: Fuel Trim Malfunction (Bank 2)

P0173 means the ECU has pushed long-term fuel trim on Bank 2 to the limit of its correction range and still cannot maintain the target air-fuel ratio. Because P0173 only affects one bank, it usually points to something specific to Bank 2 (a leak, a degraded sensor, or a dirty injector on that bank) rather than a whole-engine issue like a clogged fuel filter that would affect both banks.

P0173 è un codice diagnostico di guasto relativo a sistema di alimentazione, classificato con gravità moderate. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0173 e accende la spia motore.

Se il tuo veicolo ha attivato P0173, potresti notare uno o più di questi sintomi:

• Check engine light on
• Rough or uneven idle, especially in Park or Neutral
• Slight hesitation during acceleration
• Reduced fuel economy on one bank
• Possible faint fuel or sulfur smell from the exhaust

Ecco le cause più comuni di P0173, ordinate in base alla probabilità che siano la causa del problema:

In genere sì, per brevi tragitti. The engine can typically still be driven, but a fuel trim out of range on one bank degrades fuel economy and risks catalytic converter damage over time. Fix within a couple of weeks.

Segui questi passaggi per individuare la causa principale di P0173:

1. Read live data: focus on short-term and long-term fuel trim for Bank 2. A long-term trim above +20% or below -20% confirms the bank has been hitting its limits
2. Compare Bank 2 trims to Bank 1. If only Bank 2 is out of range, the cause is bank-specific (one injector, one sensor, one manifold gasket section)
3. Smoke-test the intake on Bank 2 specifically. On V engines, intake manifold gaskets fail one side at a time as plastic shrinks unevenly
4. Swap the upstream sensors between banks and re-check live data. If the high trim follows the sensor, replace it; if it stays on the original bank, focus on mechanical causes
5. Inspect for exhaust leaks ahead of the Bank 2 upstream sensor. A small leak can pull fresh air into the exhaust stream and trick the sensor into reading lean

I costi di riparazione di P0173 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

P0173 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:

Questi codici compaiono spesso insieme a P0173 o indicano problemi correlati: