P2AEA: Intake Air O2 Sensor Pumping Current Trim Circuit Low Bank 2
What to do
Expect worse economy and an emissions test failure; the car usually drives normally because it shuts EGR down rather than guessing. If the sensor has been replaced recently, check it was fitted with its own matched connector — these sensors carry an individual calibration, and swapping connectors produces a wrong reading that tests as healthy.
What this code means
The intake air oxygen sensor's trim current circuit on bank 2 is faulty.
This is the working half of the intake oxygen sensor whose reference voltage is at P2ABF, and the pumping current is the measurement rather than a supply to it.
A wideband sensor does not generate a reading — it is held at a target. A tiny electrochemical pump moves oxygen ions into or out of a measurement chamber, and the module varies the current until the chamber sits exactly at the ideal mixture. The current required to hold it there is the answer. More current means further from ideal; the direction says which way.
In the intake, that measurement is the EGR rate. Exhaust displaces oxygen, so intake oxygen content says directly how much of the incoming charge is recirculated — a far better number than inferring it from a valve position that soot has changed. The full argument is at P2ABF.
The trim circuit is the part that surprises people. These sensors are not identical from the factory; each is calibrated at manufacture and carries a trimming resistor, and the module reads it to correct for that individual sensor's deviation. Which is why fitting a sensor without its matched connector, or swapping the connectors between two sensors, produces a plausible and wrong reading — a real workshop error, and one no amount of testing the sensor itself will find.
Losing the pumping current disables the measurement outright, so the car cannot verify EGR rate and will normally shut EGR down rather than run it blind. That is safe for the engine and fails an emissions test.
This is the trim circuit — the calibration the module reads to correct for this individual sensor. A fault here does not stop the sensor working; it stops the correction being applied, so the reading is plausible and biased rather than absent. Check that the sensor and its connector are a matched pair before condemning either.
Likely causes
Start here
- Faulty oxygen sensor · specialist
- Corroded or loose connector · specialist
- Open circuit in sensor wiring · specialist
Less common
- Failed sensor reference voltage supply · specialist
- Damaged wiring harness · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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