Powertrain
Definition only
Lights the check engine lamp
P2A39: O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 3
Standardized SAE J2012 code · P2Axx codes
What does P2A39 mean?
Voltage on the wide-band oxygen sensor positive pump current line of bank 1 sensor 3 is below the expected window. Wire shorted to ground or pump cell short.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Common causes
- High Pump current wire shorted to ground
- Medium Internal short in pump cell
- Low Connector pins corroded - high contact resistance
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2A39 on the same make and model first.
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