OBD-II code family
Boost Control and Overspeed Faults (5 codes)
5 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P0045Turbocharger/Supercharger Boost Control Solenoid Circuit/Open
- P0046Turbocharger/Supercharger Boost Control Solenoid Circuit Range/Performance
- P0047Turbocharger/Supercharger Boost Control Solenoid Circuit Low
- P0048Turbocharger/Supercharger Boost Control Solenoid Circuit High
- P0049Turbocharger/Supercharger Turbine Overspeed
What these codes mean
P0045–P0048 concern boost-control A circuit/open, range/performance and low/high conditions in the published descriptions. P0049 concerns turbocharger or supercharger overspeed. Electrical control and actual rotational speed are different diagnostic questions; the code list does not make them one failed solenoid.
Use the complete OEM code and engine information first. Mitsubishi’s covered P0045 example describes a wastegate actuator motor circuit-high condition, illustrating why the generic label alone cannot select an open-solenoid test. The historical Isuzu VNT example also depends on its stated engine, build and calibration scope. Neither authorizes a repair on every vehicle with the same five-character code.
A variable-nozzle actuator, wastegate motor and pneumatic control solenoid can use different supplies, feedback and mechanical limits. Low/high does not directly measure boost pressure. A range/performance result does not prove the circuit passed, and an actuator command percentage does not prove vane movement.
For an overspeed fault, confirm the applicable speed-monitoring method and diagnose the operating or control cause. Do not perform a high-load road run to reproduce it, assume a universal RPM limit or replace the turbocharger from the code alone. Follow owner guidance for abnormal noise, smoke, oil loss, overheating or unsafe loss of power.
Have the specified electrical, feedback and mechanical checks performed with compatible tools. Do not move actuator stop screws, force linkages or apply battery power to unidentified terminals. Repair verification and any actuator setup follow the confirmed job. Wiring, a control device and turbocharger assembly work need different quotes.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.