P0048 means the powertrain control module has detected a higher-than-specified voltage or resistance in the turbocharger/supercharger boost control solenoid/actuator command circuit. It is an electrical circuit fault and most often points to a short-to-voltage, a failing boost control solenoid, or wiring damage rather than a mechanical turbo failure.
The solenoid valve itself can short internally or stick, pulling the circuit voltage above the expected range and setting P0048.
A wire rubbed through, pinched, or melted against a power feed can feed battery voltage back into the boost control signal line.
Poor terminal contact, pushed-out pins, or corrosion at the solenoid or PCM connector can alter circuit resistance and produce a high-side fault.
On vehicles with an electronic actuator, a shorted motor or position sensor can raise circuit voltage and trigger the code.
A rare internal fault in the PCM's boost-control driver can command or read the circuit incorrectly, but this should only be considered after wiring and the actuator are ruled out.
It is not recommended. The engine may enter limp mode, and abnormal boost control can lead to overboost or accelerated engine wear.
Usually no. This is an electrical circuit code, and the problem most often lies with the boost control solenoid, wiring, or actuator, not the turbo itself.
No. PCM failure is uncommon for this code. It should be replaced or reprogrammed only after the solenoid, wiring, and actuator have been thoroughly checked.
A vacuum leak is unlikely to set a circuit-high code; it more commonly causes performance issues or other codes. Address electrical faults first, then inspect related vacuum hoses.