Code Definition

P1149 — Heated Oxygen Sensor 1 bank 1 out of range

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

About P1149

P1149 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1149 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; 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.

P1149 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 upstream heated oxygen sensor on Bank 1, designated Sensor 1, measures exhaust oxygen ahead of the catalytic converter and provides the feedback the Engine Control Module (ECM) uses for closed loop fuel control. DTC P1149 is set when the oxygen sensor control for Bank 1 moves outside its permitted range, meaning the correction the ECM must apply to centre the mixture has exceeded the allowed limit in either the rich or lean direction. This can be caused by a genuine mixture fault, an exhaust or vacuum leak affecting the sensor, or a slow or biased sensor that the control loop can no longer...

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