Fault-Code Library · Oxygen sensing
P0130: Oxygen sensor circuit malfunction, bank 1 sensor 1
The upstream oxygen or lambda sensor signal is implausible, missing, or outside the control range expected by the ECU.
Common symptoms
- •Engine warning light
- •Poor fuel economy
- •Rough idle
- •Failed emissions test
Likely causes
- •Failed upstream oxygen sensor
- •Wiring or connector damage
- •Exhaust leak before the sensor
- •Mixture fault pushing the sensor out of range
First checks
- •Review fuel trims and sensor switching behavior
- •Inspect wiring near heat shields and exhaust
- •Check for exhaust leaks before replacing parts
Important
A lambda code can be caused by mixture or exhaust faults, not only the sensor itself.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
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