P0130
O2 Sensor Circuit Malfunction (Bank 1, Sensor 1)
The upstream oxygen sensor on bank 1 reports an implausible signal — typically stuck mid-range, no switching between rich and lean, or no signal at all. Closed-loop fuel control cannot run while this fault is active.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
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 aged or contaminatedCommon
- Sensor harness chafed against exhaustPossible
- Water in sensor connectorLess likely
Parts involved
- Oxygen Sensor Upstream
- Oxygen Sensor Wiring
P0130 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.