What it means
O2 trim line on bank 2 sensor 2 stuck high — short to B+. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 2 Sensor 2 is the oxygen sensor downstream of the catalytic converter on the engine's second cylinder bank. The control module monitors its pumping-current trim circuit, and this code sets when the circuit reads above its expected range, commonly because it is shorted to battery voltage.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Capture freeze-frame data and compare live Bank 2 Sensor 2 readings with the other oxygen sensors to check when the high reading occurs.
- Inspect the sensor connector and harness for corrosion, pushed or damaged pins, and wiring pinched against a powered wire.
- Use the wiring diagram to check whether the trim circuit is shorted to B+ and verify connector pin fit.
- With the sensor and module disconnected, test circuit continuity and isolation according to the manufacturer's procedure.
- If the circuit checks out, test Bank 2 Sensor 2 and its signal path to the module.
Common fixes
- Repair wiring pinched against a B+ source.
- Clean or repair corroded or damaged connector pins.
- Replace harness sections with insulation damage or an internal short.
- Replace Bank 2 Sensor 2 if it fails the manufacturer's test.
Can I keep driving?
If the engine runs normally, a short, cautious drive to a repair location is usually possible; avoid hard acceleration and long trips. Fuel use and emissions may increase, and rough running calls for prompt attention.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.