P0130
O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
medium
i Description
The upstream oxygen sensor on Bank 1 has a circuit malfunction. This sensor monitors exhaust oxygen content before the catalytic converter and is essential for closed-loop fuel control.
? Common Causes
- Faulty O2 sensor
- Damaged wiring or connector
- Exhaust leak near the sensor
- Contaminated sensor (oil, coolant, or silicone)
- ECU fault (rare)
! Symptoms
- Check engine light
- Poor fuel economy
- Rough idle
- Failed emissions test
- Slight power loss
# Diagnostic Steps
- Inspect O2 sensor wiring and connector
- Check for exhaust leaks near the sensor
- Monitor O2 sensor voltage with scan tool (should oscillate 0.1-0.9V)
- Test heater circuit resistance
- Replace sensor if signal is absent or stuck
⚙ Typical Fix
Replace the upstream O2 sensor on Bank 1.
Parts Needed
O2 sensor (upstream, Bank 1), Anti-seize compound
Estimated Cost
$100-$350
↔ Related Codes
Q Frequently Asked Questions
You can drive, but the engine will default to a fixed fuel map, resulting in worse fuel economy and higher emissions. Fix within a week or two.
Yes, if you have an O2 sensor socket wrench. The sensor screws into the exhaust manifold. Apply anti-seize to the new sensor threads.
O2 sensor: $50-$200. Mechanic labour: $50-$150. Total: $100-$350.
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