Emissions

P0030 — Oxygen Sensor Heater Control Circuit Fault (Bank 1 Sensor 1)

Severity: low Safe to drive

What P0030 means

The engine control module powers a heater built into the upstream oxygen sensor on Bank 1. The heater brings the sensor up to operating temperature quickly so the system can fine-tune the air-fuel mixture. P0030 is set when the module sees that the heater control circuit is not working correctly, such as an open, a short, or a power or driver problem.

Symptoms

  • Check Engine light on
  • Longer time before the engine enters closed-loop fuel control
  • Rough idle or hesitation
  • Worse fuel economy
  • Higher tailpipe emissions

Possible causes

  1. Failed heater element inside the oxygen sensor
  2. Damaged wiring or connector in the heater circuit: open, or short to ground or power
  3. Blown fuse or loss of power to the heater circuit
  4. Faulty heater relay, if the circuit uses one
  5. Failed driver circuit in the engine control module (uncommon)

How to diagnose

  1. Scan all codes and freeze-frame data, clear the code and see whether it returns
  2. Inspect the sensor harness and connector for damage, corrosion, chafing and contact with hot exhaust parts
  3. Check the heater fuse and relay using the vehicle's wiring diagram
  4. Measure the heater resistance at the sensor and compare it with the factory specification
  5. Check for power and the control signal at the sensor connector with the ignition on
  6. Test the wires back to the module for opens and shorts to ground
  7. Review live sensor data and fuel trims, and look for exhaust leaks near the sensor

Common fixes

  • Replace the Bank 1 Sensor 1 oxygen sensor
  • Repair damaged wiring or replace the connector
  • Replace the fuse or relay after finding why it failed
  • Repair or replace the engine control module if it is confirmed faulty

P0030 on different brands

Ford · manuals
On Ford, the extended code P0030:1E in the 2024-2025 gasoline-engine monitor strategy points to a Bank 1 oxygen sensor heater resistance condition; it describes what the monitor detected, not a confirmed failed part.

Questions and answers

Can I drive with a P0030 code?

Usually yes, for short trips. The engine will run, but fuel use and emissions may rise, so it's best not to delay the repair.

Do I always need a new oxygen sensor for P0030?

No. Check the fuse, wiring, connector and heater resistance first. Replace the sensor if its heater is bad while power and control are normal.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.