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P0047 Code Explained: Turbocharger/Supercharger Boost Control “A” Circuit Low Causes, Symptoms & Fixes

P0047 code displayed on an OBD-II scanner beside a turbocharger with a shorted boost control solenoid and heat-damaged actuator wiring.

If your OBD-II scanner displays P0047, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a low-voltage condition in the turbocharger or supercharger Boost Control “A” circuit.

The generic SAE description for P0047 is:

Turbocharger/Supercharger Boost Control “A” Circuit Low

This code applies to turbocharged and supercharged engines that use an electronically controlled component to regulate boost pressure. Depending on the vehicle, Boost Control “A” may refer to the:

Unlike P0045, which indicates an open circuit, or P0046, which indicates that the system is not operating within its expected range, P0047 specifically means the ECM sees lower-than-expected voltage in the Boost Control “A” circuit.

A circuit-low condition often indicates:

P0047 can result in low boost, no boost, limp mode, poor acceleration, inconsistent turbo response, or—in some cases—an overboost condition if the control system fails in the wrong position.

For more diagnostic information, visit:

P0047 Quick Facts

ItemInformation
OBD-II CodeP0047
DescriptionTurbocharger/Supercharger Boost Control “A” Circuit Low
CategoryPowertrain
SystemForced Induction / Boost Control
CircuitBoost Control “A”
SeverityModerate to High
Safe to Drive?Sometimes
Typical Repair Cost$100–1,500+

What Does P0047 Mean?

P0047 means the ECM has detected voltage below the expected range in the primary turbocharger or supercharger boost control circuit.

The ECM commands a boost control solenoid, wastegate actuator, turbo vane actuator, or supercharger bypass actuator to regulate boost pressure. It also monitors the circuit to confirm the expected amount of voltage and current is present.

If voltage remains too low, the ECM may determine that:

The exact electrical thresholds vary by vehicle manufacturer.

What Is Boost Control “A”?

The letter “A” identifies the primary boost control circuit specified by the manufacturer.

It does not automatically mean:

On a single-turbo engine, Boost Control “A” usually refers to the only wastegate or turbo actuator circuit.

On a twin-turbo or sequential-turbo engine, the manufacturer may distinguish between:

Always consult vehicle-specific wiring diagrams and service information before replacing components.

How Turbocharger Boost Control Works

A turbocharger uses exhaust energy to spin a turbine wheel. That turbine is connected to a compressor wheel that forces additional air into the engine.

More air allows the engine to burn more fuel and produce more power.

The ECM must regulate boost to prevent:

To control boost, the ECM may operate:

The ECM calculates target boost using information from:

It then adjusts the boost control component to achieve the desired pressure.

How the Boost Control “A” Circuit Works

The boost control circuit may contain:

On many systems, the boost control solenoid receives constant battery voltage while the ECM controls the ground side using pulse-width modulation.

By rapidly switching the circuit on and off, the ECM changes the amount of pressure or vacuum sent to the wastegate actuator.

On electronic wastegate systems, the ECM may directly operate an electric motor and monitor actuator position through a built-in sensor.

What Does “Circuit Low” Mean?

A circuit-low fault means the ECM sees voltage below the expected threshold.

This does not automatically mean boost pressure itself is low.

Instead, the code refers to the electrical control circuit.

Common circuit-low conditions include:

A low electrical signal may cause either low boost or high boost, depending on how the wastegate or actuator defaults when power is lost.

How the ECM Detects P0047

The ECM may set P0047 when it detects:

The code may set:

Some vehicles require the fault to occur during more than one drive cycle before illuminating the Check Engine Light.

P0045 vs P0046 vs P0047 vs P0048

CodeDescription
P0045Turbocharger/Supercharger Boost Control “A” Circuit/Open
P0046Turbocharger/Supercharger Boost Control “A” Circuit Range/Performance
P0047Turbocharger/Supercharger Boost Control “A” Circuit Low
P0048Turbocharger/Supercharger Boost Control “A” Circuit High

In general:

Symptoms of P0047

Common symptoms include:

The exact symptoms depend on how the boost control component fails.

Some systems default the wastegate open, causing low boost.

Others may fail with the wastegate closed or the turbo vanes in an aggressive position, creating an overboost risk.

Common Causes of P0047

1. Boost Control Wire Shorted to Ground

A damaged control wire may contact:

This can pull circuit voltage below the ECM’s expected range.

2. Internally Shorted Boost Control Solenoid

The electrical coil inside the boost control solenoid may short internally.

This can cause:

A shorted solenoid is one of the most common causes of P0047 on pneumatic wastegate systems.

3. Shorted Electronic Wastegate Actuator

Modern electronic wastegate actuators contain an electric motor and internal position electronics.

The actuator may fail because of:

4. Melted Wiring Near the Turbocharger

Turbocharger wiring is exposed to extreme heat.

Improperly secured wiring may melt against:

Once the insulation fails, the wire may short directly to ground.

5. Corroded Connector

Moisture, oil, road salt, and heat can damage connector terminals.

Inspect for:

Corrosion can bridge terminals and create an unintended ground path.

6. Damaged Wiring Harness

Harness damage may result from:

7. Blown Fuse

A shorted solenoid or actuator may blow the boost control fuse.

A blown fuse may also disable other components on a shared circuit.

Do not repeatedly replace the fuse without locating the short.

8. Failed Relay

Some electronic actuators receive power through a dedicated relay.

A damaged relay may create abnormal voltage conditions or intermittent operation.

9. Incorrect Replacement Solenoid or Actuator

An aftermarket component with incorrect resistance may draw more current than the ECM expects.

Potential problems include:

10. Seized Wastegate or Turbo Vanes

A mechanically seized wastegate or variable-geometry turbo mechanism can overload an electronic actuator.

The excessive motor current may pull the control circuit low and trigger P0047.

11. Contaminated Connector

Oil, coolant, moisture, or conductive debris inside the connector may create a short between terminals.

12. Failed ECM Driver

The ECM controls the boost solenoid or actuator through an internal transistor.

If that driver shorts internally, the control circuit may remain grounded and trigger P0047.

ECM failure is uncommon and should only be considered after the component and wiring have been thoroughly tested.

Is P0047 Serious?

P0047 should be considered moderately to highly serious.

A failed boost control circuit may cause:

The severity depends on the system’s mechanical default position.

A wastegate that defaults open usually causes low boost.

A wastegate that remains closed may allow boost to rise beyond safe limits.

Can You Drive With P0047?

The vehicle may still be driveable, but normal driving is not always recommended.

Short-distance driving may be possible if:

Stop driving if:

A boost control fault can make acceleration unpredictable, which is particularly unsafe when merging or passing.

How to Diagnose P0047

Step 1: Scan for Additional Codes

Record all stored, pending, and permanent codes before clearing anything.

Related codes may include:

Freeze-frame data may show whether the fault occurred during:

Step 2: Identify the Boost Control System

Determine whether the vehicle uses:

The diagnostic process varies significantly by system design.

Step 3: Inspect the Wiring Harness

Inspect wiring near the turbocharger and exhaust for:

Heat-damaged wiring is one of the most common causes of P0047.

Step 4: Inspect the Connector

Disconnect the boost control component and inspect for:

Clean or replace the connector as necessary.

Step 5: Check the Fuse

Locate the applicable boost control or actuator fuse.

Test for power on both sides of the fuse.

If the fuse is blown:

  1. Disconnect the boost control component.
  2. Install the correct replacement fuse.
  3. Switch the ignition on.
  4. Observe whether the fuse blows again.

If the fuse survives with the component disconnected, the solenoid or actuator may be shorted internally.

Step 6: Measure Solenoid or Actuator Resistance

Disconnect the component and measure resistance across the appropriate terminals.

Possible results include:

Always use vehicle-specific specifications.

Step 7: Test for a Short to Ground

With the circuit powered down and the ECM disconnected when required by the service procedure, test the control wire for unwanted continuity to ground.

Unexpected continuity may indicate:

Do not use a powered test light on sensitive ECM circuits unless the manufacturer permits it.

Step 8: Verify Power Supply

Check the boost control component’s power circuit.

Depending on the system, the component may receive:

Low supply voltage can sometimes produce misleading circuit faults, especially when a relay or connector has excessive resistance.

Step 9: Test the ECM Control Signal

Use a digital multimeter, oscilloscope, or suitable scan tool to inspect the ECM command.

On pulse-width-modulated systems, observe:

A circuit that stays near ground continuously may indicate:

Step 10: Command the Actuator With a Scan Tool

Use a bidirectional scan tool to command the boost control solenoid or actuator.

Monitor:

If current immediately exceeds specification, disconnect the component and retest the circuit.

Step 11: Inspect the Mechanical Wastegate

Check the wastegate linkage for:

A seized wastegate can overload an electronic actuator and create a circuit-low condition.

Step 12: Inspect Variable Turbo Vanes

On VGT-equipped engines, verify that the vane mechanism moves smoothly through its full range.

Carbon buildup can cause the actuator to draw excessive current while trying to move a stuck mechanism.

Step 13: Inspect Vacuum and Pressure Hoses

Although vacuum leaks do not normally create an electrical circuit-low code by themselves, damaged hoses may cause additional boost-control faults.

Inspect for:

Step 14: Check Technical Service Bulletins

Some vehicles have manufacturer bulletins involving:

Step 15: Verify the Repair

After completing repairs:

  1. Clear all diagnostic codes.
  2. Replace any blown fuse with the correct rating.
  3. Perform actuator calibration if required.
  4. Start the engine and monitor circuit voltage.
  5. Command the boost control device through its range.
  6. Road-test the vehicle under controlled load.
  7. Compare commanded and actual boost.
  8. Confirm P0047 does not return.

Common Repairs and Costs

RepairEstimated Cost
Fuse replacement$10–50
Connector repair$75–250
Wiring repair$100–500
Boost control solenoid replacement$120–400
Vacuum hose replacement$50–200
Electronic wastegate actuator replacement$300–1,200
Turbo actuator calibration$100–300
Wastegate linkage repair$200–600
Turbocharger replacement$1,200–4,500+
ECM software update$100–300
ECM replacement$1,000–2,500+

Repair costs vary depending on the vehicle and whether the actuator is sold separately.

On some modern engines, the electronic actuator is permanently paired with the turbocharger, turning what should have been a straightforward electrical repair into a premium-priced lesson in modern automotive packaging.

Common Diagnostic Mistakes

Avoid these common mistakes when diagnosing P0047:

Vehicles Commonly Affected

P0047 may appear on turbocharged or supercharged vehicles from:

It is also found on diesel engines equipped with electronically controlled variable-geometry turbochargers.

Not every manufacturer uses the same wiring design, actuator type, or diagnostic thresholds.

How to Prevent P0047

Reduce the likelihood of P0047 by:

Frequently Asked Questions

What does P0047 mean?

P0047 means the ECM has detected lower-than-expected voltage in the turbocharger or supercharger Boost Control “A” circuit.

Does P0047 mean boost pressure is low?

Not necessarily.

The word “low” refers to electrical circuit voltage, not directly to boost pressure.

The vehicle may have low boost, no boost, or even excessive boost depending on how the actuator fails.

What causes P0047 most often?

Common causes include a shorted boost control solenoid, a control wire shorted to ground, melted turbo wiring, an internally shorted actuator, or connector corrosion.

Can a bad boost control solenoid cause P0047?

Yes.

An internally shorted solenoid coil can draw excessive current and pull the circuit voltage low.

Can a bad turbocharger cause P0047?

The turbocharger itself does not usually create an electrical circuit-low code.

However, a seized wastegate or variable vane mechanism can overload the electronic actuator and contribute to P0047.

Can a blown fuse cause P0047?

A blown fuse may be present, but P0047 more commonly results from a shorted circuit or component that caused the fuse to fail.

The underlying short must be repaired.

Can I drive with P0047?

Possibly, but the vehicle may have reduced power or uncontrolled boost.

Stop driving if boost spikes, the engine knocks, heavy smoke appears, or the turbocharger makes abnormal noises.

Will replacing the boost control solenoid fix P0047?

It may if the solenoid is internally shorted.

The wiring, connector, fuse, actuator, and ECM driver should still be tested before replacing parts.

Is P0047 the same as P0045?

No.

P0045 indicates an open circuit, while P0047 indicates a low-voltage condition.

Is P0047 the same as P0048?

No.

P0047 indicates voltage is too low or current is too high. P0048 indicates voltage is too high or current is too low.

Can a boost leak cause P0047?

A boost leak usually causes underboost or performance codes such as P0299 rather than an electrical circuit-low code.

Final Thoughts

The P0047 code indicates that the ECM has detected a low-voltage condition in the turbocharger or supercharger Boost Control “A” circuit.

Unlike a mechanical underboost code, P0047 points primarily to an electrical problem. Common causes include a shorted boost control solenoid, an internally shorted electronic actuator, a control wire shorted to ground, melted wiring near the turbocharger, or a failed ECM driver.

Start diagnosis by identifying the vehicle’s boost control system. Inspect the wiring and connector, test the fuse, measure the solenoid or actuator resistance, and check the control circuit for a short to ground.

Do not replace the entire turbocharger solely because the code mentions turbo boost control. Many P0047 faults are caused by a damaged wire, connector, or replaceable solenoid. However, a seized wastegate or variable turbo mechanism can overload the actuator and may require more extensive repair.

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