All codes › P0172
P0172: System Too Rich (Bank 1)
What it means
Bank 1 is running rich (too much fuel) beyond what the computer can correct.
Severity: Medium Rich running wastes fuel and can foul plugs and the cat.
Common causes
- Leaking injector
- Faulty fuel pressure regulator
- Dirty or faulty MAF
- Faulty coolant temp sensor
- Clogged air filter
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Sometimes DIY. Check for a leaking injector or stuck-open purge valve.
Repair cost
SEEDED ESTIMATE Roughly $50–$260
Most likely repair: cleaning / no part. Diagnosis fees, taxes and other causes are not included.
| Line | Low | High | Basis |
|---|---|---|---|
| Cleaning / no part | $0 | $20 | Editorial placeholder, parts price not yet cited |
| Labor 0.5–1.5 hr | $50 | $240 | $100–$160/hr, shop survey |
⚠️ This is an editorial placeholder range for this type of repair. It is not based on real invoices or licensed pricing data yet. Real ranges will appear here once enough reader invoices for P0172 are verified.
Verified reader invoices for P0172: 0. Share your repair bill to help build real costs.
Tools that can read P0172
- ScanFixAI: Pro $29.99/mo or $249.99/yr
- OBDAI: Annual PRO bundle $299
- BlueDriver Pro Next-Gen: $119.95 list ($99.95 sale seen)
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