P0144 - O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0144 diagnostic trouble code (DTC) is defined as 'O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)'. This occurs when the Engine Control Module (ECM) detects that the signal voltage from the third oxygen sensor on bank 1 remains above the normal operating range (typically exceeding 1.2 volts). This sensor is used primarily to monitor the efficiency of the catalytic converter. High voltage on this circuit usually indicates a short to voltage in the wiring harness or a failure within the sensor's internal ceramic element that causes the signal line to bias high.
Possible Causes
Faulty Oxygen (O2) sensor (internal short in sensor 3)
Short to voltage in the wiring harness between the sensor and ECM
Corrosion or water ingress in the sensor connector terminals
Faulty Engine Control Module (ECM) or an extremely rich fuel condition (e.g., leaking fuel injector)
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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