Code Definition

P1152 — Lack Of HO2S21 Switch - Sensor Indicates Rich

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

About P1152

P1152 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1152 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.

P1152 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 code is set when the powertrain control module (PCM) detects that the upstream heated oxygen sensor (HO2S21) is not switching between rich and lean conditions as expected and remains stuck indicating a rich condition. This suggests excessive fuel delivery or a malfunctioning sensor affecting air-fuel ratio adjustments.

Quick Facts