Code Definition

P0239 — Turbocharger Boost Sensor B Circuit Malfunction

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0239

P0239 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0239 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.

Because P0239 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0239 fault code is set when the Engine Control Module (ECM) detects a malfunction in the circuit of the Turbocharger Boost Sensor B. This sensor is part of the system that measures the pressure (boost) generated by the turbocharger, but it usually refers to a secondary sensor or the sensor in a different location or turbocharger (in twin-turbo systems). The ECM uses this information to optimise engine performance by adjusting fuel injection, ignition timing, and other parameters. A malfunction in this sensor's circuit can lead to inaccurate boost pressure readings, affecting engine perfor...

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