Code Definition

P1144 — Heated Oxygen Sensor 1 bank 1 voltage high

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

About P1144

P1144 is a manufacturer-specific powertrain diagnostic trouble code recorded for Infiniti 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

The heated oxygen sensor 1 on bank 1 is the front, pre catalyst sensor the Engine Control Module (ECM) uses to monitor exhaust oxygen and control fuel trim on the bank that contains cylinder number one. DTC P1144 sets when the ECM detects that this sensor signal is biased high, meaning the voltage stays toward the rich end of its range and does not switch normally. The cause may be a genuinely rich exhaust, a contaminated sensor, or a signal circuit fault such as the signal wire shorting to a voltage source. Symptoms can include rough running, black smoke, poor fuel economy, a fuel smell and a...

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