What it means
The negative pump current control of the intake air oxygen sensor on bank 2 reports a circuit high condition. Wide-band lambda regulation on the intake side is impaired.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 intake air oxygen sensor uses a wideband pump cell to help the module regulate intake-side lambda. The module monitors the sensor's negative pump-current control circuit and sets P2AF1 when its signal is higher than expected, so wideband regulation may be impaired.
Common causes
Most likely first.
- Pump current wire shorted to B+
- Open pump cell
- Connector pins corroded - high contact resistance
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 compare bank 2 sensor data with the other bank to identify the conditions associated with the high-circuit reading.
- Inspect the bank 2 sensor connector and harness for corrosion, damaged insulation, or contact with a power feed.
- Check connector terminal fit and corrosion because high contact resistance can disrupt the control signal.
- Using the manufacturer's wiring diagram, test the negative pump-current wire for a short to battery voltage.
- If the wiring checks out, test the pump cell and sensor response by the manufacturer's procedure for an open cell.
Common fixes
- Clean or repair corroded terminals at the bank 2 intake sensor connector.
- Repair the negative pump-current wire if it is shorted to a power feed.
- Replace the bank 2 intake air oxygen sensor if its pump cell is open.
Can I keep driving?
If the engine runs normally, a short, gentle drive is generally reasonable, but avoid hard acceleration and long trips while mixture regulation may be affected. Fuel use can rise and the vehicle may fail an emissions test, so have the fault checked soon.
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.