P2A3B
O2 Sensor Negative Current Control Circuit/Open Bank 1 Sensor 3
The control circuit for the wide-band oxygen sensor negative current pump on bank 1 sensor 3 is open. Pumping current cannot be applied for lambda regulation.
- 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.
- Open in pump current wireCommon
- Internal open in pump cellPossible
- Pin pushed back out of connector bodyLess likely
Parts involved
- Oxygen Sensor B1s3
- Wiring Harness
- ECM
P2A3B 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.