What it means
The negative (sinking) side of the O2 sensor pumping current control circuit on bank 1 sensor 2 is open.
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. In a wide-band sensor, the control module uses positive and negative current-control paths to regulate oxygen in the sensor's reference chamber; this code sets when the negative, or sinking, current-control path is open.
Common causes
Most likely first.
- Open negative current line
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Record freeze-frame data and check live Bank 1 Sensor 2 data for signs the module has lost control of the downstream sensor.
- Inspect the negative current-control wire and sensor connector for heat damage, corrosion, broken wiring, or a pin pushed back into the connector body.
- Use the wiring diagram to trace the negative current path and check its continuity according to the manufacturer's procedure.
- Check connector pin retention and terminal contact at both ends of the circuit.
- If the external wiring is intact, follow the manufacturer's tests to determine whether the sensor or control module has an internal open.
Common fixes
- Reseat a displaced Bank 1 Sensor 2 connector pin and secure the connector.
- Repair an open or damaged negative current-control wire.
- Repair poor terminal contact or corrosion in the negative current path.
- Replace the sensor or repair the module only if the manufacturer's tests identify an internal failure.
Can I keep driving?
If the engine runs normally and the warning light is steady, a short drive may be possible, but avoid unnecessary trips and arrange diagnosis soon. The downstream sensor may not be controlled or monitored correctly, which can affect emissions and 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.