Code Definition

P004B — Turbo/Super Charger Boost Control Solenoid 2 Circuit Range/Performance

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

About P004B

P004B 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 P004B 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 P004B 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 P004B code indicates a problem with the range or performance of the turbocharger or supercharger boost control solenoid 2 circuit. This solenoid controls the boost pressure provided by the turbocharger or supercharger, playing a crucial role in the engine's forced induction system. The Engine Control Module (ECM) sets this code when it detects that the operation of the boost control solenoid is outside the expected range or is not performing as intended, which can lead to issues with the engine's power output and efficiency.

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