What it means
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 bank 1 intake air oxygen sensor measures oxygen using a wide-band pump cell whose current is monitored by the control module. This code sets when the pump-current circuit itself is open, so the module cannot maintain reliable intake-side oxygen feedback.
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
- Check freeze-frame data and live bank 1 intake oxygen-sensor readings for a missing signal or loss of response.
- Inspect the bank 1 sensor connector for separation, corrosion, damaged terminals, or a pin pushed back into the connector body.
- Follow the pump-current wiring from the sensor and inspect for a break, chafe, or disconnected harness section.
- Use the wiring diagram to check continuity through the pump-current circuit and connector terminals for an open.
- If the wiring and connections are intact, test the bank 1 sensor pump cell against the manufacturer's specification.
Common fixes
- Reconnect the bank 1 sensor connector and ensure its pins are fully seated.
- Repair an open or damaged pump-current wire or connector terminal.
- Replace the bank 1 intake air oxygen sensor if its pump cell has an internal open.
- Clear the code and confirm bank 1 sensor feedback returns.
Can I keep driving?
A short drive may be possible if the engine runs normally, but fuel economy and emissions can suffer while bank 1 intake oxygen feedback is unavailable. Avoid extended trips if rough running or hesitation occurs, and repair it 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.