What it means
The oxygen sensor pumping current trim circuit for bank 2 sensor 1 is open or has an open-circuit fault.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 2 sensor 1 is the upstream oxygen or air-fuel sensor on the side of the engine opposite the cylinder 1 bank, before the catalytic converter. Its pumping-current trim circuit helps the module interpret exhaust oxygen; P2629 means the module detects an open in that circuit for this sensor. The resulting loss of accurate bank 2 feedback can disrupt fuel correction.
Common causes
Most likely first.
- Open calibration trim resistor
- Open sensor connector pin
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Read freeze-frame data and compare bank 2 sensor 1 readings and fuel trims with bank 1 to identify the affected side.
- Locate bank 2 sensor 1 ahead of the catalytic converter and inspect its connector and harness for heat damage, strain, or a disconnected plug.
- Check the sensor connector terminals for a pushed-back pin, looseness, or corrosion.
- Use the wiring diagram to test continuity in the bank 2 sensor 1 trim circuit between the sensor connector and module.
- Check the sensor's internal trim circuit using the manufacturer's procedure to determine whether the open is inside the sensor.
- Clear the code after repair and verify bank 2 sensor 1 data and fuel trims during a drive cycle.
Common fixes
- Reconnect and secure the bank 2 sensor 1 connector.
- Repair the open trim wire or a pushed-back connector terminal.
- Replace heat-damaged wiring and route it clear of the exhaust.
- Replace bank 2 sensor 1 if its internal trim circuit is open.
Can I keep driving?
Gentle driving is usually possible if the engine runs smoothly, but fuel consumption and emissions can rise and the vehicle may fail an emissions test. Avoid continued driving if rough running or hesitation develops.
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.