P2A3C
O2 Sensor Negative Current Control Circuit Low Bank 1 Sensor 3
Voltage on the wide-band oxygen sensor negative pump current line of bank 1 sensor 3 is below the expected window. Wire shorted to ground or pump cell short.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Common causes
Ordered by how often each turns out to be the cause.
- Pump current wire shorted to groundCommon
- Internal short in pump cellPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Oxygen Sensor B1s3
- Wiring Harness
- ECM
P2A3C is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.