OBD-II code · Powertrain (generic, extended)
P2A39 O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 3
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.
Is it safe to drive with P2A39?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyPump current wire shorted to ground
- PossibleInternal short in pump cell
- Less likelyConnector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor B1s3, Wiring Harness, Ecm
Related codes
- P2A36AFCM Power Relay Sense Circuit Low
- P2A37AFCM Power Relay Sense Circuit High
- P2A38O2 Sensor Positive Current Control Circuit/Open Bank 1 Sensor 3
- P2A3AO2 Sensor Positive Current Control Circuit High Bank 1 Sensor 3
- P2A3BO2 Sensor Negative Current Control Circuit/Open Bank 1 Sensor 3
- P2A3CO2 Sensor Negative Current Control Circuit Low Bank 1 Sensor 3
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.