P0174 — System Too Lean (Bank 2)

P0174 is the Bank 2 version of P0171 — too much air or not enough fuel on the opposite cylinder bank. Causes are identical: vacuum leaks, dirty MAF, or fuel delivery problems.

Cost range: $10–$800. Severity: medium. Safe to drive? Drive short distances only — a lean condition damages catalytic converters quickly.

Most common causes of P0174

1. Vacuum leak on Bank 2 intake side — Smoke-test the intake to find the leak. ($10–$200)
2. Dirty MAF sensor — MAF affects both banks — clean first. ($10–$50)
3. Low fuel pressure — Affects both banks; both lean codes typically appear together. ($300–$800)

Symptoms drivers report with P0174

• Rough idle
• Stalling
• Check engine light