P0150: O2 Sensor Circuit (Bank 2 Sensor 1)
P0150 means the engine computer has found a problem in the circuit for the upstream oxygen sensor on bank 2, which helps control fuel mixture. The most common fix is repairing damaged wiring or replacing the sensor, with typical independent-shop cost around $150 to $400.
- Severity
- Moderate
- Can I drive?
- Drive with caution
- DIY?
- Possible with some experience
- Repair cost range
- $100 – $600
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What does P0150 mean?
The bank 2 sensor 1 oxygen sensor sits before the catalytic converter on the bank of the engine that does not contain cylinder 1. It measures oxygen in the exhaust so the engine computer can adjust fuel delivery in real time. When this circuit fails, the computer may not know whether the engine is running rich or lean, so it sets P0150. The problem can be caused by the sensor itself, wiring damage, connector corrosion, or an exhaust leak near the sensor.
Common symptoms
- Check engine light on
- Rough idle
- Bad gas mileage
- Hesitation on acceleration
- Failed emissions test
- Possible strong exhaust smell
Causes, fixes and costs
P0150: O2 Sensor Circuit (Bank 2 Sensor 1)
General guide for most cars. Your car may differ.
The car usually still drives, but fuel economy, idle quality, and emissions can suffer. Stop driving if the engine starts running very rough, stalls, or the check engine light flashes.
Most likely causes
- 1
Failed bank 2 sensor 1 oxygen sensorHigh
A worn or contaminated sensor is the most common reason, especially if the check engine light is on with poor fuel economy or a rough idle. If the code returns after clearing it, the sensor itself is a strong suspect.
Quick check: Inspect the sensor age and condition, then watch live data for a fixed or slow-changing signal.
- 2
Damaged wiring or loose connectorHigh
Intermittent symptoms, a code that comes and goes, or signs of heat damage near the exhaust point to a wiring issue. The sensor harness on the exhaust side is often exposed to heat, oil, and road debris.
Quick check: Look for melted insulation, broken wires, corrosion, or a connector that is not fully seated.
- 3
Exhaust leak near the sensorMedium
A leak ahead of or near the sensor can let outside air in and skew the reading, which can trigger this code along with drivability complaints. Hissing or ticking noises from the exhaust are a clue.
Quick check: Listen for exhaust leaks and inspect for soot marks around the manifold, pipe, or sensor bung.
- 4
Engine running problem affecting sensor readingsLow
Misfires, vacuum leaks, or fuel delivery problems can make the sensor circuit appear faulty, especially if the engine also has rough idle or poor acceleration. This is less likely if P0150 is the only code.
Quick check: Scan for other codes and check fuel trims and misfire data before replacing parts.
Can you fix it yourself?
Possible with some experience
Difficulty: Moderate. A basic check with a scan tool, visual inspection, and possibly a multimeter can help, but working near the exhaust requires care. If the wiring is damaged or the sensor is faulty, you need the correct replacement sensor and sometimes anti-seize, penetrating oil, and a sensor socket.
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- Read all stored and pending codes
- Inspect the bank 2 sensor 1 wiring and connector
- Check for exhaust leaks near the sensor
- Compare live O2 sensor data if your scan tool supports it
- Repair damaged wiring or replace the sensor if tests confirm failure
- Clear the code and road test
- Recheck for returning codes and fuel trim changes
Estimated repair cost
$150 – $400
Replace bank 2 sensor 1 oxygen sensor: parts about $50-$180, labor about $100-$220
- Repair oxygen sensor wiring or connector$100 – $300
- Fix exhaust leak near upstream O2 sensor$120 – $500
- Diagnose and repair engine air/fuel problem$100 – $600
Prices vary by vehicle, engine layout, and shop labor rate.
Frequently asked questions
Can I drive with P0150?
Usually yes for a short time, but you should get it checked soon. The engine may run less efficiently and may fail an emissions test.
Will P0150 clear itself?
It might go away briefly if the fault is intermittent, but it usually returns if the sensor circuit problem is still there. Clearing the code without fixing the cause will not solve it.
Is P0150 the same as a bad catalytic converter?
No. P0150 is an oxygen sensor circuit code, not a catalyst efficiency code, though an exhaust or engine problem can sometimes contribute to the reading.
Can I replace the oxygen sensor myself?
Yes, if you can safely reach the sensor and the wiring is not badly damaged. Rust, heat, and tight access can make the job harder than it looks.
Will P0150 cause bad gas mileage?
Yes, it can. When the computer cannot trust the bank 2 upstream O2 sensor signal, it may use a less accurate fuel mixture and waste fuel.
Related codes
Related problems
This guide covers most cars and is general advice, not an inspection. Prices are typical US independent-shop ranges and vary by region, car and shop. If your brakes, steering or a warning light feel unsafe, stop driving and contact a mechanic.