What it means
The bank 1 sensor 2 oxygen sensor pumping current trim circuit is above the expected range. The code does not by itself establish a short to voltage or predict mixture effects.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 Sensor 2 is the downstream oxygen sensor on the bank containing cylinder 1. The control module monitors its pumping-current trim circuit and sets this code when the circuit reads above its expected range; the code alone does not establish a short 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
- Save freeze-frame data and check live Bank 1 Sensor 2 readings to establish when the pumping-current trim circuit goes high.
- Inspect the trim wire and connector for pinching against a power source, heat damage, corrosion, or loose terminals.
- Use the wiring diagram to trace the trim circuit and check for an unintended connection to battery voltage.
- Check terminal contact and circuit continuity using the manufacturer's procedure.
- If the wiring is sound, test the downstream sensor and module circuit against the manufacturer's specification.
Common fixes
- Repair trim wiring pinched against a power source or damaged by heat.
- Clean or repair corroded or loose connector terminals.
- Correct a confirmed short to battery voltage in the trim circuit.
- Replace the sensor or repair the module only if testing confirms an internal fault.
Can I keep driving?
If the engine runs normally and the warning light is steady, keep driving to necessary trips and avoid hard acceleration until diagnosed. The fault can interfere with downstream sensor control and emissions monitoring, and may affect fuel economy.
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.