What P0030 means
The heater circuit inside the upstream oxygen sensor is not behaving as expected, so the sensor takes too long to reach operating temperature.
Common causes
- Failed oxygen sensor heater element
- Blown fuse feeding the sensor heater
- Damaged or corroded wiring/connector near the exhaust
How it is usually fixed
- 1Check the fuse and connector before replacing anything
- 2Measure heater circuit resistance against specification
- 3Replace the upstream oxygen sensor if the heater is open
Other common codes
- P0011 — Camshaft Position A – Timing Over-Advanced (Bank 1)
- P0101 — Mass Air Flow Circuit Range/Performance
- P0113 — Intake Air Temperature Sensor Circuit High
- P0118 — Engine Coolant Temperature Sensor Circuit High
- P0131 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
- P0138 — O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
Code information is general guidance, not a diagnosis for a specific vehicle. Confirm with live data and manufacturer test procedures before replacing parts.