P0047: Turbocharger/Supercharger Boost Control A Circuit Low

"Boost control A" is the electrically driven actuator the engine control module uses to set boost pressure: depending on the engine a pulse-width modulated solenoid or vacuum converter at the wastegate, the control valve of variable turbine vanes, or an electric actuator with position feedback. The letters A and B denote two separate actuators, for example on the low- and high-pressure turbocharger of a two-stage system, not the cylinder banks. This code is set when the voltage at the control output is too low, typically because of a short to ground; some manufacturers also report a missing supply this way. Without control the actuator usually falls back to its rest position, which on most engines means low boost; depending on the design too much boost is also possible.

Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

Symptoms

Check engine light on
Loss of power or reduced power mode
Weak acceleration, noticeable turbo lag
Overboost possible in rare cases

Most likely causes

Harness chafed, short to ground
Actuator coil shorted
Water in the connector
Output driver in the engine control module faulty

What to check, in order

Start with the simplest. You can tick off each step.

Check the hoses, clamps, and intercooler
With the connector unplugged, check whether the signal wire is making contact with ground.
Compare commanded and actual pressure in live data
Check the actuator's movement
Check the vacuum hoses and the solenoid valve
Check the oil and the turbo shaft play before replacing it

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P0047 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
0: Subsystem depends on the code range
47: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0047?

Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

What causes code P0047?

The most common causes are: harness chafed, short to ground; actuator coil shorted; water in the connector.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.