OBD-II code · Powertrain (generic)
P0173 Fuel Trim Malfunction Bank 2
Fuel trims on bank 2 exceed adaptation limits in either lean or rich direction. The ECU cannot maintain stoichiometric mixture within calibrated boundaries.
Is it safe to drive with P0173?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOxygen sensor bank 2 aged
- PossibleVacuum leak bank 2 side
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor, Mass Air Flow Sensor, Fuel Injector, Intake Manifold
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.