P0150: O2 Sensor Circuit (Bank 2 Sensor 1)
On a V6 or V8, the upstream oxygen sensor on bank 2 has a signal problem.
What P0150 means
P0150 is the bank 2 version of P0130. It only shows up on engines with two banks, usually V6 or V8 engines. Bank 2 is the side opposite cylinder 1, and sensor 1 is the upstream sensor before the catalytic converter. The engine computer relies on this sensor to fine tune fuel on that side of the engine. P0150 means the signal is out of range, stuck, or not switching as expected. A worn sensor, wiring cooked by exhaust heat and exhaust manifold leaks are the common causes. A cracked exhaust manifold or leaking gasket on bank 2 pulls outside air past the sensor, which throws off its reading. On many transverse V6 engines, bank 2 or bank 1 sits against the firewall, which can make the sensor harder to reach and raise labor. Shops compare bank 1 and bank 2 sensor activity, check fuel trims, test the wiring and look for exhaust leaks before replacing the sensor.
Common symptoms
- Check engine light on
- Worse gas mileage
- Rough idle on some engines
- Failed emissions test
- Often no other symptoms
Most common causes
- Failing bank 2 upstream oxygen sensor
- Wiring damaged by exhaust heat
- Exhaust manifold leak on bank 2
- Engine running rich or lean on bank 2
- Corroded connector
What to check yourself first
Bank 2 is the side of the engine without cylinder 1. Find the sensor before the catalytic converter on that side and check its wiring for heat damage. Listen for a ticking exhaust manifold leak on a cold start.
Typical fixes and what they cost
| Fix | Typical cost | Note |
|---|---|---|
| Replace oxygen sensor | $440-$523 | Bank 2 upstream sensors on some V6 engines sit against the firewall and take longer to reach. |
| Electrical diagnosis to find a wiring or connector fault | $122-$179 | For heat damaged wiring. |
| Check engine light diagnosis at a shop | $125-$183 | Rules out an exhaust leak or fuel mixture problem. |
Typical US price ranges for parts and labor, not quotes. Your shop should confirm the cause with a diagnostic before replacing parts.
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Related codes
- P0151 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
- P0155 O2 Sensor Heater Circuit (Bank 2 Sensor 1)
- P0130 O2 Sensor Circuit (Bank 1 Sensor 1)
- P0174 System Too Lean (Bank 2)
- P0430 Catalyst System Efficiency Below Threshold (Bank 2)