What it means
The heater control circuit for the Bank 1 Sensor 2 heated oxygen sensor is reporting voltage above the expected range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 Sensor 2 is the heated oxygen sensor downstream of the catalytic converter on the bank containing cylinder 1. The control module monitors the electrical circuit for this sensor's heater. P0044 sets when the circuit voltage is higher than expected, which can happen if wiring is shorted to battery voltage or the supply wire contacts a powered source.
Common causes
Most likely first.
- Heater wiring shorted to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Oxygen-sensor heater may warm slowly
- Fuel economy may decrease
- Emissions may increase
How to diagnose it
- Check freeze-frame data and related codes to see when the Bank 1 Sensor 2 heater circuit voltage went high.
- Inspect the sensor connector and harness for pinched wires, heat damage, corrosion, or contact with a battery-voltage wire.
- Use the wiring diagram to identify the Bank 1 Sensor 2 heater supply and control wires, then check for voltage where it should not be present.
- Test the harness for a short to battery voltage and inspect connector pins for poor contact or corrosion.
- If the harness checks out, test the sensor heater and module control circuit according to the manufacturer's procedure.
Common fixes
- Repair Bank 1 Sensor 2 heater wiring that is shorted to battery voltage.
- Reroute or secure a pinched supply wire away from powered wiring and hot exhaust parts.
- Repair corroded or damaged connector pins to restore reliable contact.
- Replace the Bank 1 Sensor 2 sensor if its heater fails the specified test.
Can I keep driving?
If the vehicle drives normally, a short gentle trip for diagnosis is usually reasonable, but do not ignore the circuit fault because the sensor heater may not operate correctly and emissions can rise. Stop and seek prompt help if the fault is accompanied by smoke, a burning smell, or severe engine symptoms.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.