Fuel and air code
P0174: Engine getting too much air or too little fuel (bank 2)
On the engine bank that does not hold cylinder 1, the oxygen sensor keeps reporting too much air for the fuel being sent. The computer is already adding as much fuel as it is allowed to and still cannot fix the mix, so it sets this code and the check-engine light.
- Safe to drive?
- Usually yes, for now
- Most common cause
- Vacuum leak or cracked intake hose
Short drives are usually okay, but fix it soon; stop if the engine stumbles, stalls or the check-engine light flashes.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $5 | $60 |
| Labor: 0.8 to 2.5 hours × $125 to $175 an hour | $100 | $438 |
| Fees: shop supplies, disposal, diagnostics | $0 | $25 |
| Total, rounded | $100 | $530 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, vacuum leak repair. Which repair your car needs depends on a proper diagnosis.
What you may notice
- Rough idle
- Surging at steady speed
- Hesitation under load
Common causes, most likely first
- Vacuum leak or cracked intake hose
- Dirty mass airflow sensor
- Weak fuel pump or clogged filter
- Leaking intake manifold gasket
- Clogged fuel injector on that side
Check this first
If P0171 is on at the same time, the cause is probably shared, like the airflow sensor or fuel pressure. Check the air-intake tube and vacuum hoses first.
Other repairs that sometimes fix P0174
| Repair | Typical range, Boston |
|---|---|
| Mass airflow sensor replacement | $130 to $410 |
| Fuel pump replacement | $400 to $1,150 |
| Fuel injector replacement (one injector) | $180 to $910 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0174 questions
Why do I have both P0171 and P0174?
When both banks run lean, the cause is usually something shared by the whole engine, such as the airflow sensor, a large vacuum leak at the intake, or low fuel pressure. One bank alone points more to a local leak.
Can bad gas cause this?
It can. Water in the fuel or a bad tank of gas can make the mixture act lean for a while. If the light came on right after filling up, tell the shop which station and when so they can factor it in.
How much does a smoke test cost?
Many shops charge a diagnostic fee for a smoke test. Harmless smoke is fed into the intake, and the shop watches for wisps that show where air is leaking in. It is often faster than guessing at parts.
How much does it cost to fix P0174?
The most common fix, vacuum leak repair, has a typical range of $100 to $530 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
P0174 repair cost by city
Related codes
- P0171: Engine getting too much air or too little fuel (bank 1)
- P0175: Engine getting too much fuel (bank 2)
- P0101: Air flow sensor reading seems off
- P0300: Random or multiple cylinder misfires
More fuel and air codes
Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.