Ask Andy AIP0174 System Too Lean (Bank 2)
What it means, what causes it, and what it costs to fix.
What P0174 means
Same as P0171, but on bank 2. When P0171 and P0174 show up together, the problem affects the whole engine: a large vacuum leak, the MAF sensor, or low fuel pressure. If it's only bank 2, look for a leak or injector issue on that side.
Can I drive with P0174?
Severity: Medium. Fix soon so it doesn't turn into something bigger.
Usually drivable short term, but fix it soon. Lean running raises engine temperatures and can cause misfires.
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Ask Andy about P0174Symptoms
- Check engine light
- Rough idle
- Hesitation
- Possible misfires
Common causes
Most likely first.
- Vacuum leak (if both banks are lean, look for something shared, like the PCV or intake)
- Dirty or failing MAF sensor
- Low fuel pressure
- Leaking intake gasket on the bank 2 side
How to diagnose P0174
- Note whether P0171 is also set. Both together point to a shared cause.
- Compare bank 1 and bank 2 fuel trims in live data.
- Smoke-test for vacuum leaks, then clean or test the MAF, then check fuel pressure.
Tip: most US auto parts stores will read your codes for free.
Repair costs
| Vacuum leak repair | $20–$600 |
| MAF sensor | $10 cleaning to $350 installed |
| Fuel pump or filter | $150–$1,200 |
Typical US prices. Your vehicle, region, and shop rates will change these.
P0174 FAQ
What does P0174 mean?
P0174 means "System Too Lean (Bank 2)." Same as P0171, but on bank 2. When P0171 and P0174 show up together, the problem affects the whole engine: a large vacuum leak, the MAF sensor, or low fuel pressure. If it's only bank 2, look for a leak or injector issue on that side.
Can I drive with a P0174 code?
Usually drivable short term, but fix it soon. Lean running raises engine temperatures and can cause misfires.
What is the most common cause of P0174?
The most common cause is: Vacuum leak. Other causes include dirty or failing maf sensor and low fuel pressure.
How much does it cost to fix P0174?
Typical repairs run about $10 to $1,200 in the US, depending on the cause. Vacuum leak repair: $20–$600.
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