P0130: OBD-II code P0130 flags a generic fault in the upstream O2 sensor circuit on bank 1 — the signal is out of range or invalid but not specifically stuck low or high.

Symptoms

• Check engine light is on; the engine may run rich or lean depending on the sensor's bias.
• Fuel economy drops as the PCM defaults to open-loop fuel maps without valid O2 feedback.
• Rough idle and mild hesitation from lack of closed-loop trim compensation.

Common causes

• A failed upstream O2 sensor with intermittent output or a stuck reference voltage.
• Damaged sensor wiring or a corroded connector at the sensor.
• Contamination on the sensor tip from silicone gasket sealer, coolant, or oil burning past the rings.

What to do?

Read live O2 voltage during idle and light throttle — it should switch cleanly between about 0.1 V and 0.9 V once the sensor is warm. Inspect the sensor tip visually. Replace the sensor if it fails to switch or shows contamination on the ceramic element.