Code Definition

P1133 — Air/Fuel Sensor circuit Response

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

About P1133

P1133 is a manufacturer-specific powertrain diagnostic trouble code recorded for Lexus vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1133 is stored, the module has detected 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.

P1133 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

This Lexus monitors the upstream air fuel ratio sensor to control fuel delivery in closed loop. As part of its self diagnostics the Engine Control Module (ECM) periodically checks how quickly the sensor responds to forced changes in mixture. DTC P1133 sets when the air fuel ratio sensor on Bank 1 Sensor 1 responds too slowly when switching between rich and lean, indicating a lazy or aged sensor. When the code is stored the engine may show reduced fuel economy, slightly rough running, and the ECM may limit closed loop fuel correction.

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