P0174
Moderate severityFuel System Too Lean (Bank 2)
Drivable short-term, but check it soon to avoid running hot and causing damage. If it appears with P0171, the cause is usually shared by both banks.
What does the P0174 code mean?
The P0174 code means Bank 2 of the engine is running lean — too much air or not enough fuel. It is the Bank 2 version of P0171 and only appears on engines with two banks (V6, V8).
When P0171 and P0174 show up together, both sides are lean, which usually points to one shared cause — most often a large vacuum leak or a MAF sensor problem — rather than two separate faults.
Can you keep driving with a P0174 code?
Yes, with care, short-term. Like any lean code it raises combustion temperatures over time, so don’t leave it for long. Check it within a week, sooner if the engine idles rough or hesitates.
What causes a P0174 code?
- Large vacuum leak affecting both banks~35%
- Dirty or failing MAF sensor~30%
- Weak fuel delivery (pump, filter, injectors)~20%
- PCV or intake leak~15%
How to diagnose a P0174 (check these first)
- If you also have P0171, look for a shared cause first — a big vacuum leak or the MAF.
- Smoke-test the intake for vacuum leaks.
- Clean the MAF sensor with MAF-safe cleaner.
- Check fuel pressure if both banks read lean.
P0174 repair cost
Typical US ranges including parts and labor (varies by vehicle):
| Vacuum leak repair | $75 – $300 |
| MAF sensor | $80 – $250 |
| Fuel pump / filter | $200 – $700 |
Tools & parts that help
A scanner plus a can of MAF cleaner are the cheapest first steps; a smoke test (DIY or at a shop) quickly finds vacuum leaks.
See MAF cleaners & scanners ›P0174 — Frequently asked questions
Is it safe to drive with a P0174 code?
Short-term yes, but get it checked within a week to avoid running lean and hot for too long.
What does P0174 mean?
It means Bank 2 of the engine is running lean – too much air or too little fuel on that side of the engine.
Why do I have both P0171 and P0174?
Both banks reading lean usually means one shared cause, such as a large vacuum leak or a faulty MAF sensor.
Can a dirty MAF sensor cause P0174?
Yes, a dirty or failing MAF sensor is one of the most common causes of lean codes on both banks.
Related codes
General guidance based on the standard definition of the P0174 code. A real diagnosis depends on your make, model, mileage and other symptoms. When in doubt, have a professional confirm the cause before replacing expensive parts.