Code Definition

P0039 — Turbo/Super Charger Bypass Valve Control Circuit Range/Performance

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

About P0039

P0039 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 P0039 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.

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 P0039 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

DTC P0039 is a range or performance fault in the control circuit for the turbocharger or supercharger bypass valve, the valve that vents or recirculates charge pressure so the forced induction system is not overloaded. The Engine Control Module commands this valve, or its control solenoid, and compares the expected result against boost and valve feedback; P0039 sets when the circuit is electrically present but its behaviour is out of the expected range, so the valve responds slowly, incompletely, or not in step with the command. This differs from a plain circuit code because the wiring can tes...

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