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P0044 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 1 Sensor 3)

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P0044 code definition

P0044 is a specific code that is set when high voltage is found in the heater control circuit. This code may be seen with P0042 and P0043.

What the P0044 code means

P0044 is set by the engine control unit (ECU) when excessively high voltage is found for the heater control circuit on bank 1 sensor 3. This high voltage creates an inaccurate reading from the heated oxygen sensor causing the ECU to turn on the Check Engine Light.

What causes the P0044 code?

There are multiple causes for the P0044, they are as follows:

  • Heated oxygen sensor bank 1 sensor 3 failure
  • Open or shorted wiring to ground
  • Poor connection for heated oxygen sensor
  • Faulty ECU

What are the symptoms of the P0044 code?

The vehicle's ECU runs checks on sensors multiple times a second. When the ECU tries to control the heated oxygen sensor and finds high voltage it causes a Check Engine Light to illuminate. This causes faulty readings from the heated oxygen sensor. Rarely, this may cause the vehicle to run poorly and a decrease in fuel milage may be noticed.

How does a mechanic diagnose the P0044 code?

A qualified technician will have no trouble diagnosing a P0044 code. The first thing they will do is hook up a scan tool to the OBD-II port to confirm that P0044 is present along with any other codes. Freeze frame data that is associated with all codes will be observed for engine speed, operating temperature, time, and other conditions under which the code occurred.

Then the code will be cleared and a road test will be performed to duplicate the conditions seen in the freeze frame data. If P0044 reappears, then the technician will inspect the wiring and heated oxygen sensor for damage, visual wiring open, or shorted or broken wires. Then the sensor will be inspected for proper orientation. If all of the previous tests check out okay, the ECU will be inspected for any faults.

Common mistakes when diagnosing the P0044 code

Mistakes are found when simple items are skipped or steps are not followed. Though the sensor failure is the most common cause of P0044, all steps must be followed and the heated oxygen sensor must be diagnosed before it is replaced.

How serious is the P0044 code?

In most cases other than the Check Engine Light, no symptoms are noticed or felt during normal driving. Any drivability symptoms should be addressed immediately.

What repairs can fix the P0044 code?

The most common repairs are:

Additional comments for consideration regarding the P0044 code

Oxygen sensors are meant to last the life of the vehicle, though with higher milage they are known to fail due to contaminants in gasoline. The sensor must be tested before it is condemned and replaced.

Need help with a P0044 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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