What it means
The negative pump current control of the intake air oxygen sensor on bank 1 reports a circuit low 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 uses a wide-band pump cell to help the control module assess oxygen in incoming air. P2AE7 sets when the module sees the negative pump-current control circuit at an abnormally low electrical level, which can occur if the wire is grounded or the sensor circuit is shorted.
Common causes
Most likely first.
- Pump current wire shorted to ground
- Internal short in 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 review bank 1 sensor readings and fuel corrections to establish whether the low condition occurs continuously or only under certain conditions.
- Inspect the bank 1 intake-air sensor connector for corrosion, moisture, bent terminals, or poor terminal contact.
- Follow the negative pump-current wire and check for insulation rubbed through against the engine or body, especially near hot or moving parts.
- Use the manufacturer's wiring diagram and specified test method to determine whether the circuit is shorted to ground, with the sensor and module isolated as directed.
- If the harness is not grounded, test the bank 1 sensor pump cell per the manufacturer's procedure for an internal short before replacing the sensor.
Common fixes
- Clean and properly secure corroded or loose bank 1 sensor connector terminals.
- Repair insulation damage or a negative pump-current wire shorted to ground.
- Replace terminals that have lost reliable contact.
- Replace the bank 1 intake-air oxygen sensor if its pump cell is internally shorted.
Can I keep driving?
If the engine runs smoothly, a short, gentle drive is generally possible, but fuel consumption and emissions may worsen while bank 1 intake-side regulation is impaired. Avoid prolonged driving if it hesitates or idles roughly.
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.