02-12-2021
13 min.
3110

P0246 Turbocharger / Supercharger Wastegate Solenoid "A" Circuit High

P0246 is an OBD-II diagnostic trouble code indicating that the engine control module (ECM) has detected an abnormally high electrical condition in the control circuit of Turbocharger/Supercharger Wastegate Solenoid �A.�

The wastegate system controls turbocharger boost by regulating how much exhaust energy reaches the turbine. The ECM uses a wastegate solenoid or actuator to control this process according to engine load, speed, throttle position, requested torque, and intake pressure.

The most important part of this code is “Circuit High.”

In P0246, “high” generally refers to an electrical voltage or control condition that is higher than the ECM expects. It does not automatically mean that the engine has excessive boost pressure.

Therefore, P0246 should not immediately be interpreted as:

Turbocharger failure
Excessive boost
Wastegate stuck closed
Supercharger failure

The actual cause may be as simple as a damaged wire contacting battery voltage or a faulty connector.

What Does P0246 Mean?

The ECM electrically controls Wastegate Solenoid “A” and monitors the circuit.

When the ECM commands the solenoid, it expects the circuit voltage and electrical response to remain within a specific range.

If the monitored circuit remains at a voltage higher than the calibrated limit, the ECM can store P0246.

Depending on the vehicle's electrical architecture, this can be caused by:

Short to battery voltage
Incorrect voltage in the control circuit
Faulty solenoid
Internal solenoid electrical failure
Damaged wiring
Connector problems
Incorrect power supply
ECM driver failure

The exact circuit design varies between manufacturers.

Some systems use a conventional vacuum-control solenoid, while others use electronically controlled wastegate actuators.

What Is Wastegate Solenoid “A”?

Wastegate Solenoid “A” is part of the turbocharger boost-control system.

On a conventional turbocharged engine, the ECM may control a solenoid that regulates vacuum or pressure going to the wastegate actuator.

The actuator then moves the wastegate.

A typical system may contain:

ECM
Wastegate Solenoid “A”
Vacuum source
Vacuum hoses
Wastegate actuator
Wastegate linkage
Turbocharger
MAP/boost-pressure sensor

However, not every engine uses the same architecture.

Some engines use electronic wastegate actuators with an integrated motor and position sensor rather than a simple vacuum solenoid.

The designation “A” is manufacturer-specific.

It should not automatically be assumed that “A” means the first turbocharger or a particular physical location.

What Is a Wastegate?

The wastegate is a boost-control mechanism.

A turbocharger uses exhaust gas to spin a turbine. The turbine drives a compressor wheel that pressurizes the intake air.

As engine load increases, more exhaust energy becomes available to the turbocharger.

The wastegate allows some exhaust gas to bypass the turbine when necessary.

When more exhaust gas is directed through the turbine, turbocharger speed and boost can increase.

When the wastegate opens and bypasses exhaust gas, turbocharger energy is reduced.

The ECM therefore uses the wastegate system to keep boost within the desired operating range.

What Does “Circuit High” Mean?

“Circuit high” is one of the most commonly misunderstood descriptions in OBD diagnostics.

In P0246, it generally means the ECM has detected higher-than-expected electrical voltage or another high electrical condition in the Wastegate Solenoid “A” circuit.

It does not necessarily mean:

High turbo boost
High intake pressure
High exhaust pressure
High engine RPM
Turbocharger overspeed

For example, if the ECM uses a control wire to switch the solenoid and that wire becomes shorted to battery voltage, the ECM can detect a circuit-high condition.

The turbocharger may still be mechanically healthy.

Common Causes of P0246

Several faults can trigger P0246.

Short to battery voltage

A damaged control wire can contact a battery-voltage source.

This is one of the first possibilities that should be considered with a circuit-high code.

Faulty wastegate solenoid

The solenoid may have an internal electrical fault, including abnormal coil resistance or an internal short.

Damaged wiring

The harness can become:

Melted
Chafed
Broken
Pinched
Corroded
Incorrectly repaired

Turbocharger wiring is particularly vulnerable to heat.

Corroded connector

Moisture, oil, dirt, and corrosion can alter the electrical characteristics of the circuit.

Loose terminal

A connector can appear properly installed while one terminal has insufficient contact pressure.

Incorrect replacement solenoid

A replacement solenoid with different electrical characteristics may not be compatible with the ECM's control strategy.

Incorrect power supply

A fuse, relay, shared supply, or wiring problem can cause abnormal voltage at the solenoid.

ECM driver fault

The ECM contains an electronic driver that controls the solenoid. If the driver fails, the control circuit can behave abnormally.

This should generally be investigated only after the solenoid and wiring have been verified.

Symptoms of P0246

The symptoms vary depending on how the ECM responds to the fault.

Possible symptoms include:

Check Engine Light
Reduced engine power
Poor acceleration
Turbo lag
Irregular boost
Hesitation
Surging
Limp mode
Poor fuel economy
Excessive boost
Insufficient boost

Some vehicles may continue operating normally apart from the warning light.

Others may immediately limit turbocharger operation to protect the engine.

Can P0246 Cause High Boost?

It can be associated with an overboost condition, but P0246 itself does not mean that excessive boost has been measured.

If the wastegate cannot open when required, exhaust energy can continue driving the turbocharger.

This can produce excessive boost.

Possible causes include:

Wastegate stuck closed
Actuator failure
Solenoid malfunction
Blocked control hose
Incorrect vacuum routing
Mechanical linkage problem

However, an actual overboost condition and a circuit-high fault are two different diagnostic issues.

A mechanically stuck wastegate can cause overboost without necessarily causing P0246.

Can P0246 Cause Low Boost?

Yes.

If the ECM detects a wastegate-control problem, it may enter a protective strategy and reduce turbocharger output.

A wastegate that remains too open can also allow too much exhaust gas to bypass the turbine.

The result can be:

Low boost
Slow acceleration
Reduced power
Turbo lag

However, low boost has many other possible causes, including:

Charge-air leaks
Intercooler leaks
MAP sensor problems
MAF problems
Vacuum leaks
Exhaust restrictions
Turbocharger mechanical problems

P0246 Does Not Automatically Mean Turbocharger Failure

This is one of the most important diagnostic points.

The turbocharger may be mechanically perfect while P0246 is caused by an electrical fault.

For example, suppose the wiring harness near the exhaust manifold becomes heat-damaged and the Wastegate Solenoid “A” control wire contacts battery voltage.

The ECM can detect a high circuit condition and store P0246.

Replacing the turbocharger would not solve the problem.

Likewise, a turbocharger can have mechanical damage without producing P0246.

The code should therefore be treated as a wastegate control-circuit fault, not a direct turbocharger-failure code.

How to Diagnose P0246

A systematic diagnosis should begin with the electrical circuit.

1. Scan All Diagnostic Trouble Codes

Start by scanning the vehicle and recording all stored and pending DTCs.

Look for related codes involving:

Turbocharger control
Boost pressure
MAP sensor
MAF sensor
Wastegate position
Engine voltage
Communication

Additional codes may provide an important clue.

2. Check Freeze-Frame Data

Record the conditions under which P0246 was stored.

Useful information includes:

Engine RPM
Engine load
Vehicle speed
Engine temperature
Throttle position
MAP pressure
Boost pressure
Battery voltage

If the fault occurs only under acceleration, inspect the wiring for movement and engine vibration.

3. Identify Wastegate Solenoid “A”

Use manufacturer-specific service information to identify the actual component.

Determine:

Solenoid location
Connector pinout
Power supply
Ground/control circuit
ECM control terminal
Expected resistance
Control strategy

Do not assume that the generic code description identifies the exact component on every engine.

4. Inspect the Connector

Disconnect the solenoid and inspect the connector carefully.

Look for:

Corrosion
Bent pins
Loose terminals
Water intrusion
Oil contamination
Heat damage
Broken locking mechanism

A poor connection can create difficult-to-reproduce electrical problems.

5. Inspect the Wiring Harness

Follow the harness toward the ECM.

Pay particular attention to wiring near:

Turbocharger
Exhaust manifold
Downpipe
Heat shields
Engine brackets

Look for:

Melted insulation
Chafing
Broken conductors
Previous repairs
Exposed wires
Incorrect routing

Because P0246 is a circuit-high code, an unintended connection to battery voltage is especially important.

6. Test for Short to Battery Voltage

The Wastegate Solenoid “A” control circuit should be tested for an unintended connection to battery voltage.

The exact procedure depends on the manufacturer's electrical architecture.

The ECM and solenoid should be isolated appropriately before resistance testing.

7. Check Power and Ground

Verify that the solenoid receives the correct power supply and ground/control path.

Do not assume that because voltage is present at one terminal, the complete circuit is healthy.

Voltage-drop testing under load can reveal problems that a simple static voltage measurement may miss.

8. Measure Solenoid Resistance

If the manufacturer provides a resistance specification, measure the solenoid coil.

An open circuit or significantly abnormal resistance can indicate an internal electrical problem.

However, resistance alone cannot prove that the solenoid operates correctly.

A solenoid can have acceptable resistance but fail when:

Hot
Energized
Vibrating
Operating at a particular duty cycle

9. Check the ECM Control Signal

Many wastegate solenoids are controlled using PWM.

An oscilloscope can be useful for checking:

PWM waveform
Duty cycle
Switching behavior
Voltage level
Intermittent faults
Electrical noise

This is particularly useful when a conventional multimeter cannot capture a brief fault.

Test the Mechanical Side Separately

Once the electrical circuit is verified, test the physical wastegate-control system.

On a vacuum-operated system, inspect:

Vacuum source
Vacuum hoses
Control valve
Wastegate actuator
Linkage

A vacuum pump can be used where appropriate to determine whether the actuator moves and holds the specified vacuum.

Inspect Wastegate Actuator Movement

The actuator should move smoothly through its specified travel.

Check whether it:

Begins moving at the correct pressure/vacuum
Reaches the required position
Moves smoothly
Holds vacuum/pressure
Provides correct position feedback where applicable

A defective actuator can create boost-control symptoms even when the solenoid electrical circuit is perfect.

Inspect the Wastegate Linkage

The mechanical linkage should move freely.

Possible problems include:

Rust
Carbon deposits
Seized pivot
Bent linkage
Excessive play
Disconnected linkage

If the linkage is mechanically stuck, replacing the solenoid may not solve the problem.

Compare Commanded and Actual Boost

After checking the control system, compare:

Commanded boost

with

Actual boost

using live data.

This can help determine whether the engine is actually experiencing:

Underboost
Overboost
Normal boost with an electrical fault

If actual boost is significantly different from the requested value, investigate the complete boost-control system.

Check the MAP Sensor

The ECM depends on pressure information to determine whether boost control is working correctly.

A faulty MAP sensor can report incorrect pressure.

Check:

Sensor power
Ground
Signal
Wiring
Connector
Live-data values

Compare the sensor reading with a known pressure reference where appropriate.

Check for Boost Leaks

If the vehicle has low boost, inspect the complete charge-air system.

Check:

Turbocharger outlet
Intercooler
Intercooler hoses
Intake pipes
Clamps
Seals
Plastic charge pipes

A pressure or smoke test can reveal leaks that are difficult to find visually.

A boost leak is not normally the direct cause of an electrical circuit-high code, but it can exist simultaneously and create similar performance symptoms.

P0246 on Variable Geometry Turbochargers

Not every turbocharged engine uses a traditional wastegate.

A variable geometry turbocharger (VGT/VNT) uses adjustable vanes to regulate exhaust flow and turbocharger response.

Some generic diagnostic databases group related control systems under wastegate terminology even when the physical mechanism is different.

On such systems, diagnosis may involve:

Electronic actuator
Vane position
Position sensor
Vacuum control
Turbocharger vanes
Boost pressure

Therefore, always verify the actual turbocharger architecture before replacing a wastegate component.

P0246 on Twin-Turbo Engines

The letter “A” is especially important on engines with multiple turbochargers or boost-control devices.

Depending on the manufacturer, “A” may identify:

One specific turbocharger
One wastegate solenoid
One actuator
One boost-control circuit

It should not automatically be interpreted as “the first turbo.”

Manufacturer-specific service information is required to identify the correct component.

Can a MAP Sensor Cause P0246?

A MAP sensor can cause incorrect boost-control decisions, but it does not normally create a genuine electrical high condition in the Wastegate Solenoid “A” circuit.

If P0246 is stored by itself, concentrate first on:

Solenoid
Wiring
Connector
Power supply
Control circuit

If MAP-related codes are also present, investigate both systems.

Can a Vacuum Leak Cause P0246?

A vacuum leak can cause poor wastegate operation on vacuum-controlled systems.

However, it does not normally explain the electrical circuit-high portion of P0246.

If both an electrical code and boost-control symptoms are present, test both the electrical and vacuum sides of the system.

Common Diagnostic Mistakes

Replacing the turbocharger immediately

P0246 is a wastegate solenoid circuit code, not a direct turbocharger failure code.

Assuming “high” means high boost

It generally refers to an electrical condition.

Replacing the solenoid without checking the wiring

A short to battery voltage can cause the same code with a perfectly good solenoid.

Ignoring heat damage

Turbocharger wiring is exposed to extreme temperatures.

Checking only resistance

Resistance testing may miss intermittent faults or problems that occur when the solenoid is energized.

Ignoring the mechanical actuator

The solenoid can function electrically while the actuator or wastegate is mechanically stuck.

Ignoring actual boost data

Commanded versus actual boost can help distinguish an electrical fault from a genuine boost-control problem.

Replacing the ECM too early

An ECM driver fault should normally be considered only after the external circuit and solenoid have been verified.

P0246 vs P0243, P0244, P0245, P0248 and P0250

These codes are closely related but identify different fault conditions.

P0243 – Turbocharger/Supercharger Wastegate Solenoid “A” Circuit Malfunction

A broad malfunction in the “A” wastegate solenoid circuit.

P0244 – Wastegate Solenoid “A” Range/Performance

The “A” wastegate control system is not behaving within its expected range.

P0245 – Wastegate Solenoid “A” Circuit Low

The ECM detects an abnormally low electrical condition.

P0246 – Wastegate Solenoid “A” Circuit High

The ECM detects an abnormally high electrical condition in the “A” circuit.

P0248 – Wastegate Solenoid “B” Range/Performance

The “B” wastegate control system is not responding within its expected operating range.

P0250 – Wastegate Solenoid “B” Circuit High

The ECM detects an abnormally high electrical condition in the “B” circuit.

The key distinction is that P0246 identifies Solenoid “A” and a circuit-high condition, while P0244 is primarily a range/performance problem and P0250 moves to the “B” circuit.

A Practical Diagnostic Order

A logical diagnostic sequence for P0246 is:

Scan all modules and record every DTC.
Save freeze-frame data.
Identify the exact Wastegate Solenoid “A.”
Determine the turbocharger control architecture.
Inspect the solenoid connector.
Inspect the wiring harness, especially around hot components.
Check power and ground.
Test the control circuit for shorts to battery voltage and ground.
Measure solenoid resistance according to manufacturer specifications.
Check the ECM control signal.
Use an oscilloscope if the fault is intermittent or PWM-controlled.
Inspect vacuum or pressure-control hoses.
Test wastegate actuator movement.
Inspect wastegate linkage.
Check MAP/boost-pressure sensor operation.
Inspect the charge-air system for leaks.
Compare commanded and actual boost.
Evaluate the turbocharger mechanically if the previous tests are normal.
Consider an ECM driver fault only after the rest of the system has been verified.

Final Diagnosis

P0246 – Turbocharger/Supercharger Wastegate Solenoid “A” Circuit High indicates that the ECM has detected an abnormally high electrical condition in the Wastegate Solenoid “A” control circuit.

The most likely areas to investigate are the solenoid, wiring, connector, power supply, control circuit, and ECM driver. The mechanical wastegate, actuator, vacuum/pressure system, MAP sensor, and actual boost pressure should also be checked when drivability symptoms are present.

Most importantly, P0246 does not automatically mean high boost and does not automatically mean that the turbocharger has failed.

A damaged wire shorted to battery voltage can produce P0246 while the turbocharger itself remains completely healthy. Conversely, a mechanically stuck wastegate can cause an actual boost problem without producing this electrical code.

The correct repair should therefore be based on electrical circuit testing, solenoid testing, actuator operation, and commanded-versus-actual boost data, rather than replacing the turbocharger simply because P0246 is stored.