Code Definition

P004A — Turbo/Super Charger Boost Control Solenoid 2 Circuit Open

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

About P004A

P004A 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 P004A is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit.

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 P004A 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 turbocharger or supercharger boost control solenoid 2 is an Engine Control Module (ECM) driven valve that regulates the vacuum or pressure signal applied to the wastegate actuator or the variable geometry vane actuator, allowing the ECM to hold manifold boost at the commanded target. The solenoid is normally supplied with battery voltage through the main relay or an ignition fed fuse and switched on its ground side by a pulse width modulated ECM driver, with the ECM continuously monitoring that circuit for correct current flow. DTC P004A is set when the ECM detects an open circuit in the s...

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