What it means
The trim adjustment for the pumping current of the intake air oxygen sensor on bank 1 reports a circuit open 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 intake air oxygen sensor is a wide-band sensor that measures oxygen in the intake stream, and its pump cell uses a controlled current to support the measurement. The module sets this code when the bank 1 pumping-current trim circuit is open, preventing reliable adjustment of that current.
Common causes
Most likely first.
- Open in pump current wire
- Internal open in pump cell
- Pin pushed back out of connector body
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 intake oxygen-sensor data for a missing or implausible reading.
- Inspect the bank 1 sensor connector for a loose fit, corrosion, damage, or a terminal pushed back into the connector body.
- Trace the pump-current trim wiring from the bank 1 sensor and look for breaks, chafing, or a disconnected section.
- With the wiring diagram, check circuit continuity through the pump-current trim wire and its connector terminals for an open.
- If the harness and terminals are intact, test the bank 1 sensor pump cell against the manufacturer's specification.
Common fixes
- Reconnect the bank 1 sensor plug and secure it so its terminals remain seated.
- Repair a broken pump-current trim wire or damaged connector terminal.
- Replace the bank 1 intake air oxygen sensor if its pump cell is open.
- Clear the code and confirm the sensor data and fuel control respond normally.
Can I keep driving?
The vehicle may remain driveable, but fuel economy and emissions can worsen while bank 1 intake oxygen feedback is unreliable. Avoid extended driving if the engine runs roughly or hesitates, and repair the fault before an emissions inspection.
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.