P2243
O2 Sensor Reference Voltage Circuit (Bank 1 Sensor 1)
The reference voltage line that powers the wide-band sensor cell on bank 1 sensor 1 is missing or out of tolerance. Without correct reference, the AFR calculation is invalid.
- 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.
- Reference voltage line openCommon
- Wide-band sensor failedPossible
Parts involved
- Oxygen Sensor Wideband
- Oxygen Sensor Wiring
P2243 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.