P0174 System Too Lean Bank 2

P0174 means the control module reports a lean condition on bank 2. It is similar to P0171, but the affected bank matters when checking vacuum leaks, exhaust leaks, injectors, and sensor data.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System
Fuel / Air
Scope
iso-sae-controlled-p0
Standard
SAE J2012 / ISO 15031-6
Source
legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace both upstream sensors automatically; bank-to-bank trim comparison usually gives a better diagnostic direction.

Useful checks before replacing parts

Related OBD-II codes

These nearby fuel / air entries can help compare wording and fault area. They may share the same verification status as the source database.