P0047 — Low voltage in turbo boost control solenoid circuit

The code indicates a problem with the electrical circuit controlling the turbocharger's boost pressure. It usually means the boost control solenoid is not getting the right voltage or has a wiring issue. This can cause poor engine performance or reduced power because the turbo isn't regulated properly.

Common causes

The cause is almost always one of a few things. Here they are — P0047 rarely comes from anything outside this list:

• Faulty boost control solenoid
• Damaged or corroded wiring/connectors
• Blown fuse or relay related to solenoid circuit
• ECU or sensor malfunction

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Check and repair wiring and connectors for damage or corrosion
2. Test and replace blown fuses or relays if needed
3. Test boost control solenoid operation and replace if faulty
4. Inspect ECU and sensors if problem persists

That is what holds for P0047 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.