All codes › P0131
P0131: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
What it means
Voltage from the upstream O2 sensor on bank 1 (before the catalytic converter), which the computer uses to adjust fuel mixture is stuck low, which looks like a constant lean signal.
Severity: Low–Medium Can mask a real lean problem; check fuel trims.
Common causes
- Failed sensor
- Exhaust leak pulling in air
- Signal wire shorted to ground
- Actual lean condition
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Often DIY. Rule out exhaust leaks near the sensor before replacing.
Repair cost
SEEDED ESTIMATE Roughly $70–$330
Most likely repair: oxygen sensor. Diagnosis fees, taxes and other causes are not included.
| Line | Low | High | Basis |
|---|---|---|---|
| Oxygen sensor | $36 | $168 | Typical listed retail range, source |
| Labor 0.3–1 hr | $30 | $160 | $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 P0131 are verified.
Verified reader invoices for P0131: 0. Share your repair bill to help build real costs.
Tools that can read P0131
- 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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