P2A00
O2 Sensor Circuit Range/Performance Bank 1 Sensor 1
O2 Sensor Circuit Range/Performance Bank 1 Sensor 1: the signal is implausible or outside the valid range.
- 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.
- Oxygen sensor agingCommon
- Sensor contamination (oil, silicone)Possible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Oxygen Sensor
- Oxygen Sensor Wiring
P2A00 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.