What Does P0144 Mean?
The ECM has detected that the oxygen sensor on Bank 1 Sensor 3 is producing a voltage signal above the expected maximum. On a conventional zirconia O2 sensor, this means the voltage is consistently above 0.9V or stuck at the high end of its range, indicating the sensor is either reading a persistent rich condition or has an internal fault. Since Sensor 3 monitors a secondary catalytic converter, this does not directly affect fuel control but compromises emissions monitoring.
Common Causes
35%
Failed O2 sensor (Bank 1 Sensor 3) with sensing element stuck producing high voltage
25%
O2 sensor signal wire shorted to the heater power wire or another voltage source
20%
Contaminated O2 sensor (oil or fuel saturation) causing a persistent rich reading
10%
Actual rich exhaust condition reaching Sensor 3 due to a failing upstream catalytic converter allowing unburned fuel through
10%
ECM internal bias or pull-up fault on the Sensor 3 input circuit
Diagnostic Steps
1
Monitor Bank 1 Sensor 3 live data. If the voltage is stuck above 0.9V and does not fluctuate regardless of engine operating conditions, the high-voltage fault is confirmed.
2
Disconnect the O2 sensor connector and check if the ECM reading drops to the 0.45V bias voltage. If it does, the wiring is intact and the sensor is producing the high voltage internally.
3
If the voltage stays high with the sensor disconnected, check the signal wire for a short to voltage (heater power, 12V, or 5V source). Measure from signal wire to chassis ground for unexpected voltage.
4
Inspect the O2 sensor for contamination — remove and check the tip for black sooty deposits (rich running) or oily residue (oil burning).
5
If the exhaust system has multiple catalytic converters, verify the upstream cats are functioning properly. A failed upstream cat passing unburned fuel can cause the downstream sensor to read rich.
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
The ECM has detected that the oxygen sensor on Bank 1 Sensor 3 is producing a voltage signal above the expected maximum. On a conventional zirconia O2 sensor, this means the voltage is consistently above 0.9V or stuck at the high end of its range, indicating the sensor is either reading a persistent...
The most common cause of P0144 (02 Sensor Circuit High Voltage (Bank 1 Sensor 3)) is: Failed O2 sensor (Bank 1 Sensor 3) with sensing element stuck producing high voltage
Typical repair costs for P0144 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. Bank 1 Sensor 3 does not influence fuel trim calculations. The MIL will be illuminated and emissions testing will fail, but there is no driveability or safety risk from this code alone.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0144 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions / Exhaust
Difficulty
Type
Generic (SAE)
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