P0150
O2 Sensor Circuit Bank 2 Sensor 1
Fuel & air metering / O2 sensor
Generic OBD-II
Medium
What it means
P0150 means the ECM detected a general circuit fault with the upstream oxygen sensor on bank 2 (sensor 1, before the catalytic converter). That sensor reports the air/fuel mixture so the engine can trim fuel in closed loop. With it faulted, the ECM loses accurate feedback for that bank, so the car keeps running but with worse fuel economy and emissions. Bank 2 is the side of the engine that doesn't contain cylinder 1.
Medium
Can I keep driving? Safe to drive — the engine runs, but fuel control on bank 2 is off, so expect worse economy and emissions until the sensor is fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Poor fuel economy
- Slightly rough running or hesitation
- Failed emissions test
Common causes
Most likely first
- Failed upstream (bank 2, sensor 1) O2 sensor — most commonLikely
- Damaged wiring or a corroded connector at the sensorCommon
- Exhaust leak near the sensor skewing its readingCommon
- Vacuum leak affecting the bank 2 air/fuel mixtureLess often
- Rarely, an ECM faultLess often
How to diagnose & fix
Work through it in order
- Scan the live bank 2, sensor 1 O2 data and check whether it switches normally or is stuck/flatlined.
- Inspect the sensor's connector and wiring for corrosion, damage, or heat melting.
- Check for exhaust leaks ahead of the sensor and vacuum leaks on bank 2.
- Replace the upstream bank 2 O2 sensor if it fails to respond, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0150?+
Yes, in the short term. The engine still runs, but with the bank 2 upstream sensor faulted the ECM can't fine-tune that bank's mixture, so fuel economy and emissions suffer. It's not an emergency but shouldn't be ignored.
Can I just clear P0150?+
It will return once the ECM re-tests the sensor if it's still faulty. Replacing the sensor or repairing its circuit is what keeps the code off.
Related codes
Often seen with P0150
Read & clear P0150 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX