P0249 indicates that the engine control module has detected a low voltage or low circuit condition in the control side of turbocharger/supercharger wastegate actuator or regulator solenoid “B.” The “Low” condition usually means the commanded signal is lower than expected, often due to a short to ground, open circuit, or a failed solenoid. This can prevent proper wastegate regulation and affect boost control.
The solenoid that controls vacuum or pressure to the wastegate actuator can fail internally, causing a low signal or no response. This is the single most common cause of P0249.
A short to ground, open wire, corrosion, or poor pin connection between the solenoid and the PCM can produce a low voltage reading and set the code.
Cracked, disconnected, blocked, or leaking hoses between the solenoid and the wastegate actuator can prevent proper actuator movement and confuse control feedback.
A seized, broken, or misadjusted wastegate actuator arm or valve can cause abnormal load on the solenoid circuit or incorrect position feedback.
An internal failure of the engine control module could misread or incorrectly drive the solenoid, but this is uncommon and should only be considered after mechanical and electrical causes are ruled out.
Short trips are usually possible, but poor boost control can reduce power and increase engine stress; it is best to diagnose and repair it promptly.
Usually not. Most cases are caused by the wastegate control solenoid, wiring, or vacuum hoses, not the turbocharger itself.
No, the PCM is rarely the cause. P0249 is most often fixed by replacing a failed solenoid, repairing wiring, or correcting vacuum leaks. Replace the PCM only after all other causes are genuinely ruled out.
You can clear it to verify whether the fault is active, but if the underlying electrical, mechanical, or vacuum problem remains, the code will usually return quickly.