Damaged, chafed or shorted wiring to the boost control solenoid or actuator; Corroded, loose or contaminated connector at the actuator or control unit; Faulty boost control solenoid, wastegate actuator or variable geometry actuator; Low or unstable supply voltage or poor earth to the actuator circuit; Heat damage to wiring or actuator near the turbocharger; Internal fault in the engine control unit driver circuit.

P0047

Turbocharger/Supercharger Boost Control A Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
47: FaultThe specific fault in that area

What it means

P0047 means the engine control unit has detected a low voltage or low signal in the electrical circuit that controls the turbocharger or supercharger boost control device 'A'. This is usually a wastegate or variable geometry vane actuator, solenoid or electric motor. The fault is set when the commanded and measured circuit state do not agree, which points to a short to ground, high resistance or an open circuit. Exact device type and layout depend on the model and engine.

Symptoms

Engine warning light on
Loss of power or reduced boost
Car goes into limp mode
Poor acceleration, especially under load
Turbo whistle, over-boost or erratic boost behaviour
Increased fuel consumption or black smoke on some diesels

Possible causes

Damaged, chafed or shorted wiring to the boost control solenoid or actuatorlikely
Corroded, loose or contaminated connector at the actuator or control unitlikely
Faulty boost control solenoid, wastegate actuator or variable geometry actuatorlikely
Low or unstable supply voltage or poor earth to the actuator circuitpossible
Heat damage to wiring or actuator near the turbochargerpossible
Internal fault in the engine control unit driver circuitrare

How to diagnose

Read all stored and pending codes and note freeze frame data, then check for related boost, actuator position or supply voltage codes
Check for relevant technical service bulletins and model-specific procedures for the engine fitted
Visually inspect the wiring and connectors from the actuator or solenoid to the control unit, looking for chafing, heat damage, water ingress and corrosion
Check the battery condition and charging voltage, and inspect the relevant fuses, relays and earth connections
Using live data, command the actuator and watch whether the commanded and actual positions or duty cycle follow each other
Measure the actuator or solenoid resistance and compare it with the manufacturer's specification
Test the circuit for short to ground, open circuit and high resistance, and check the supply and signal at the connector
Check that the actuator linkage or vanes move freely and are not seized or sooted, where accessible

How to fix

Repair or replace damaged wiring and fix any short to ground or open circuit
Clean, repair or replace corroded or loose connectors and terminals
Replace the faulty boost control solenoid or actuator, then carry out any adaptation or calibration the manufacturer requires
Restore good supply voltage and earth connections, and replace faulty fuses or relays
Free or replace a seized turbo linkage or vanes if mechanical sticking is found
Replace or repair the control unit only after all wiring and components have been proven good

Can I keep driving?

Medium severity

The car can usually be driven short distances in limp mode, but power will be reduced and uncontrolled boost can stress the engine or turbo. Have it diagnosed soon and avoid heavy loads until it is fixed.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.