P0044 indicates that the powertrain control module (PCM) has detected a voltage higher than expected in the heater control circuit for the upstream oxygen sensor (HO2S) on Bank 1, Sensor 3. The heater circuit is used to bring the sensor to operating temperature quickly; an abnormally high voltage usually points to a short to power or a faulty sensor heater.
The internal heater of the oxygen sensor has shorted to power, causing the PCM to see an excessive voltage in the heater control circuit.
Damaged insulation or chafed wiring allowing the heater control wire to contact a power source, producing a high voltage reading.
Poor connection or corrosion can cause abnormal voltage readings in the heater circuit, mimicking a short.
Although less common for a 'high' code, excessive resistance can cause the PCM to interpret the circuit as out of range, sometimes triggering a high voltage fault.
The PCM’s internal driver for the heater circuit could be stuck high, but this is uncommon and should be considered only after wiring and sensor checks.
No. The PCM is rarely at fault for this code; most cases are due to a failed sensor heater or wiring issue. PCM replacement should only be considered after confirming the sensor and its circuit are good.
You can usually drive the vehicle, but the oxygen sensor may not reach operating temperature quickly, which can affect fuel economy and emissions. It is advisable to repair the fault to avoid potential emissions test failure and to maintain optimal engine performance.
Clearing the code only turns off the check‑engine light temporarily. If the underlying heater circuit fault remains, the code will return once the PCM runs its self‑test again.
The code itself does not pose a direct safety risk, but prolonged operation with a faulty oxygen sensor can lead to increased emissions and reduced catalytic converter efficiency over time.