P0044 Code – HO2S Heater Control Circuit High (Bank 1 Sensor 3)
P0044 is an OBD-II generic diagnostic trouble code indicating that the Engine Control Module (ECM) has detected a high voltage condition in the heater control circuit of the Heated Oxygen Sensor (HO2S) at Bank 1 Sensor 3.
Code Meaning
P0044 – HO2S Heater Control Circuit High (Bank 1 Sensor 3)
Symptoms
- Check Engine Light (MIL) illuminated.
- Reduced fuel economy.
- Higher exhaust emissions.
- Delayed oxygen sensor operation after startup.
- Usually little or no noticeable drivability issues.
Possible Causes
- Faulty Bank 1 Sensor 3 oxygen sensor heater.
- Short to battery voltage in the heater circuit.
- Damaged or melted wiring harness.
- Loose or corroded electrical connector.
- Faulty ECM (rare).
Sensor Location
Bank 1 Sensor 3 is positioned downstream of the catalytic converter(s) on the cylinder bank containing cylinder number 1. This sensor is used only on vehicles equipped with a third oxygen sensor.
How to Diagnose
- Read and confirm DTC P0044 using an OBD-II scanner.
- Inspect the sensor connector and wiring for damage.
- Check for excessive voltage in the heater circuit.
- Measure heater resistance with a digital multimeter.
- Verify proper power and ground supply.
- Replace the oxygen sensor if the heater element has failed.
Common Repairs
- Replace Bank 1 Sensor 3 oxygen sensor.
- Repair shorted heater wiring.
- Repair or replace damaged connectors.
- Repair the heater power circuit.
- Clear the DTC and perform a road test.
Can You Drive with P0044?
Yes. The vehicle can generally be driven, but emissions and fuel efficiency may be negatively affected until the fault is repaired.
Related OBD-II Codes
- P0042 – HO2S Heater Control Circuit (Bank 1 Sensor 3)
- P0043 – HO2S Heater Control Circuit Low (Bank 1 Sensor 3)
- P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
- P0161 – O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)