Code Definition

P1144 — Heated Oxygen Sensor 1 bank 1 voltage high

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Nissan

About P1144

P1144 is a manufacturer-specific powertrain diagnostic trouble code recorded for Nissan vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1144 is stored, the module has detected a signal or supply voltage higher than the expected operating range; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1144 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

Heated oxygen sensor 1 is the front, pre catalyst oxygen sensor on bank 1, which compares exhaust oxygen against outside air and generates roughly 1V when the mixture is rich and near 0V when it is lean. The ECM uses this signal to trim the injection pulse and keep the air fuel ratio near stoichiometric. DTC P1144 is a rich shift monitoring fault, set when the front sensor signal stays biased high, meaning it reads rich more than expected or its switching point has shifted rich. This usually points to a genuinely rich mixture or a contaminated front sensor that no longer swings lean correctly....

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