Diagnostic Trouble Code (DTC) P0242 Turbocharger/Supercharger Boost Sensor B Circuit High is a generic code applicable to most vehicles equipped with a turbocharger, including brands such as VW, Dodge, Mercedes, Isuzu, Chrysler, Jeep, etc.

Boost System Operation

The Powertrain Control Module (PCM) regulates turbocharger pressure via a boost solenoid. To adjust this pressure, the PCM monitors in real-time the data sent by the boost pressure sensor.

How Does the Boost Sensor Work?

This sensor acts as a variable resistor:

• The PCM sends a 5V reference signal to the sensor.
• When pressure is low, resistance is high → only a low voltage (approximately 0.5V) is returned to the PCM.
• When pressure increases, resistance decreases → the voltage returned to the PCM increases (up to 4.5V at maximum boost).

Code P0242 triggers when the PCM detects a voltage above 4V on the sensor “B” circuit, while no boost is requested.

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Common Symptoms

When this code appears:
✅ Check Engine Light (CEL) illuminates.
✅ The PCM enters limp mode (limited boost and timing).
✅ Noticeable loss of power (vehicle in “safe mode”).
⚠️ Risk of catalytic converter damage if the problem persists.

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Possible Causes

1️⃣ Other associated DTCs (e.g., faulty IAT sensor, ECT sensor, or 5V circuit).
2️⃣ Wiring problem (damaged wires, corroded connectors).
3️⃣ Faulty boost sensor “B”.
4️⃣ Short to voltage in the sensor circuit.
5️⃣ Faulty PCM (less common).

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Diagnostic Procedures

🔧 1. Check Technical Service Bulletins (TSB)
Some vehicles have known issues with solutions published by the manufacturer.

🔧 2. Inspect for intermittent faults (wiggle test)

• With engine running, gently shake the sensor harness to detect poor contact.

🔧 3. Electrical measurements (digital multimeter)

• KOEO (Key On, Engine Off):
  • Disconnect the sensor → check for 5V on the supply.
  • If 5V is absent → PCM or circuit problem.
• Sensor connected:
  • Normal KOEO voltage ≈ 0.5V. If abnormal → faulty sensor.

⚠️ To avoid:
❌ Do not use an incandescent test light (risk of damaging the circuit).

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Conclusion

Code P0242 indicates a high voltage signal problem with the boost sensor. A methodical check of the wiring, sensor, and associated codes is essential to resolve the issue effectively. If the diagnosis is uncertain, further analysis with a specialized scan tool may be necessary.

🚗 Recommended quick solution: Replace the faulty sensor or repair the circuit as needed.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to turbocharged and supercharged engines, including but not limited to certain Audi, Ford, GM, Mercedes, Mitsubishi, VW, and Volvo vehicles.

The Powertrain Control Module (PCM) controls the boost pressure in a gasoline or diesel engine by managing the output circuit to the wastegate/boost control solenoid valve “A”.

Whenever there is an electrical issue with this circuit that it cannot otherwise identify, the PCM will set the P0243 code. This code is considered an electrical circuit fault only.

Troubleshooting steps may vary depending on the manufacturer, the type of wastegate/boost pressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0243 engine code may include:

Malfunction Indicator Light illuminated
Instrument cluster message alerting the driver to the condition
Lack of power

Causes

Causes

Possible reasons for setting this code are as follows:

Open in the control circuit (ground circuit) between the wastegate/boost control solenoid valve A and the PCM
Open in the power supply circuit between the wastegate/boost control solenoid valve A and the PCM
Short to ground in the power supply circuit of the wastegate/boost control solenoid valve A
Wastegate/boost control solenoid valve A
Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money during diagnosis.

Next, locate the wastegate/boost control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for scratches, rubbing, exposed wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if P0243 returns. If not, the connections were likely your problem.

If the code returns, we will need to test the solenoid and its associated circuits. Typically, there are 2 wires to the wastegate/boost control solenoid. First, disconnect the wiring harness going to the wastegate/boost control solenoid. With a digital volt-ohm meter (DVOM), connect one meter lead to one terminal of the solenoid. Connect the remaining meter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance/0 ohms), replace the solenoid.

If this test passes, with a DVOM, ensure you have 12V on the wastegate/boost control solenoid power supply circuit (red lead to the solenoid power supply circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that is okay, check that the wastegate/boost control solenoid is properly grounded. Connect a test light to the 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the wastegate/boost control solenoid circuit ground. Using the scan tool to activate the wastegate/boost control solenoid, check if the test light illuminates each time the scan tool activates the solenoid. If the test light does not illuminate, it would indicate a circuit problem. If it illuminates, wiggle the wiring harness going to the solenoid to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0243 code, it would most likely indicate a faulty wastegate/boost control solenoid, although a faulty PCM cannot be ruled out until the solenoid has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.

What does error code P0244 mean?

The diagnostic code P0244 is a generic powertrain/engine code. It generally applies to vehicles equipped with turbocharged and supercharged engines, including, but not limited to, certain models from Ford, Mercedes, and Subaru.

The Powertrain Control Module (PCM) regulates the boost pressure in a gasoline or diesel engine by controlling the output circuit to the “A” Wastegate/Supercharger Bypass Valve Control Solenoid.

The P0244 code is stored by the PCM when it detects a problem with the overall boost control operating range or boost-related performance that cannot be attributed to other circuit fault codes. This code can indicate a fault in the electrical circuit or a mechanical problem with the engine, depending on the exact nature of the issue.

It is important to note that troubleshooting steps can vary significantly depending on the vehicle manufacturer, the type of wastegate/supercharger boost pressure control system used, and the color of the control solenoid wires.

Possible symptoms of code P0244

Symptoms associated with a P0244 engine code may include:

• The Malfunction Indicator Lamp (MIL or Check Engine Light) is illuminated.
• A message may appear on the dashboard (instrument cluster) to alert the driver of the problem.
• Lack of engine power.

Potential causes of code P0244

Several factors can lead to this code being stored:

• Open circuit (break) in the control circuit (ground circuit) between the “A” Wastegate/Supercharger Bypass Valve Control Solenoid and the PCM.
• Open circuit (break) in the power supply circuit between the “A” Wastegate/Supercharger Bypass Valve Control Solenoid and the PCM.
• Short to ground in the power supply circuit of the “A” Wastegate/Supercharger Bypass Valve Control Solenoid.
• Short to power in the power supply circuit of the “A” Wastegate/Supercharger Bypass Valve Control Solenoid.
• Faulty “A” Wastegate/Supercharger Bypass Valve Control Solenoid.
• PCM (Powertrain Control Module) failure (although this is considered very unlikely).

Diagnostic and repair procedures

The first recommended step is to check the Technical Service Bulletins (TSBs) specific to your vehicle. The manufacturer may have published information regarding a known issue and a solution, which could save you time and money.

Next, locate the “A” Wastegate/Supercharger Bypass Valve Control Solenoid on your vehicle. Once located, perform a visual inspection of the associated connectors and wiring. Look for signs of rubbing, scraping, bare wires, burning, or melted plastic. Disconnect the connectors and carefully inspect the metal terminals inside. Check if they are burnt or show a greenish discoloration indicating corrosion. If terminal cleaning is necessary, use an electrical contact cleaner and a plastic-bristled brush. Let it dry and apply dielectric grease to the terminals before reconnecting.

The author emphasizes that the most common cause of this code is often related to electrical connection or vacuum problems.

If you have a scan tool (OBD-II scanner), clear the fault codes from the PCM’s memory and observe if the P0244 code returns. If it does not, the problem was likely related to a poor connection.

If the code reappears, it will be necessary to test the solenoid and its associated circuits. Generally, the wastegate/supercharger bypass valve control solenoid has two wires.

1. Solenoid Test: Disconnect the solenoid connector. Using a digital multimeter (DVOM) set to ohms, connect the probes to the two terminals of the solenoid. The solenoid should not be open (infinite resistance) or shorted (zero or very low resistance). Consult the resistance specifications for your specific vehicle. If the solenoid is open or shorted, replace it.

2. Power Supply Check: With the ignition ON and using the DVOM set to volts, check if approximately 12 volts is present on the solenoid’s power supply circuit (red multimeter lead on the solenoid’s power supply wire, black lead on a good vehicle ground). If no voltage is present, or if voltage is present when the ignition is OFF, there may be a wiring problem between the PCM or a relay and the solenoid, or potentially a faulty PCM.

3. Ground Check: To check the solenoid’s ground, connect a test light to the positive (+) terminal of the battery (red terminal) and touch the other end of the test light to the solenoid’s ground circuit. Using the scan tool, activate the wastegate/supercharger bypass valve control solenoid. The test light should illuminate each time the scan tool activates the solenoid. If the test light does not illuminate, this indicates a problem in the ground circuit. If it does illuminate, wiggle the wiring harness going to the solenoid to see if the light flickers, which would indicate an intermittent connection.

4. Mechanical and Vacuum Check (if applicable): Ensure all associated mechanical components are properly secured and operate freely. If the system uses vacuum to actuate the valve, verify that there is sufficient vacuum at the control solenoid. If not, locate the source of the blockage or leak in the vacuum circuit.

If all previous tests are conclusive and the P0244 code persists, it is likely that the wastegate/supercharger boost pressure control solenoid is faulty. Although a faulty PCM is unlikely, it cannot be completely ruled out until the solenoid has been replaced. If in doubt, it is recommended to consult a qualified automotive technician. PCMs often require specific vehicle programming or calibration to function correctly after replacement.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to turbocharged and supercharged engines, including but not limited to some Audi, Ford, GM, Mercedes, Mitsubishi, VW, and Volvo vehicles.

The Powertrain Control Module (PCM) controls the boost pressure in a gasoline or diesel engine by managing the output circuit to the wastegate/boost control solenoid valve “A”.

Depending on how the manufacturer activates the solenoid, when the PCM provides power or ground to energize the solenoid and the PCM detects that there is no voltage in the circuit at any time when there should be (off), the PCM will set the P0245 code. This code is considered an electrical circuit fault only.

Troubleshooting steps may vary depending on the manufacturer, the type of wastegate/boost pressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0245 engine code may include:

Malfunction indicator light illuminated
Instrument cluster message alerting the driver to the condition
Lack of power

Causes

Causes

Possible reasons for setting this code are as follows:

Open in the control circuit (ground circuit) between the wastegate/boost control solenoid valve A and the PCM
Open in the power supply circuit between the wastegate/boost control solenoid A and the PCM
Short to ground in the power supply circuit of the wastegate/boost control solenoid A
Wastegate/boost control solenoid valve A
Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money during diagnosis.

Next, locate the “A” wastegate/boost control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for scratches, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Allow to dry and apply electrical grease where the terminals make contact.

The most common failure is due to connection problems.

If you have a scan tool, clear the diagnostic codes from the memory and see if P0245 returns. If not, the connections were likely your problem.

If the code returns, we will need to test the solenoid and its associated circuits. Typically, there are 2 wires to the wastegate/boost control solenoid. First, disconnect the wiring harness going to the wastegate/boost control solenoid. With a digital volt ohm meter (DVOM), connect one meter lead to one terminal of the solenoid. Connect the remaining meter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance/0 ohms), replace the solenoid.

If this test passes, with a DVOM, ensure you have 12V on the wastegate/boost control solenoid power circuit (red lead to the solenoid power circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that is okay, check that the wastegate/boost control solenoid is properly grounded. Connect a test light to the 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the wastegate/boost control solenoid circuit ground. Using the scan tool to activate the wastegate/boost control solenoid, check if the test light illuminates each time the scan tool activates the solenoid valve. If the test light does not illuminate, it would indicate a circuit problem. If it lights up, wiggle the wiring harness going to the solenoid to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0245 code, it would most likely indicate a failing wastegate/boost control solenoid, although a faulty PCM cannot be ruled out until the solenoid has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to turbocharged and supercharged engines, including but not limited to some Audi, Ford, GM, Mercedes, Mitsubishi, VW, and Volvo vehicles.

The Powertrain Control Module (PCM) controls the boost pressure in a gasoline or diesel engine by managing the output circuit to the wastegate/boost control solenoid valve “A”.

 

Depending on how the manufacturer activates the solenoid, when the PCM provides power or ground to energize the solenoid and the PCM detects that voltage is already present in a circuit where it shouldn’t be, the PCM will set code P0246. This code is considered an electrical circuit fault only.

Troubleshooting steps may vary depending on the manufacturer, the type of wastegate/boost pressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0246 engine code may include:

    Malfunction Indicator Light illuminated
    Instrument cluster message alerting the driver to the condition
    Lack of power

Causes

Causes

Possible reasons for setting this code include:

    Open in the control circuit (ground circuit) between the wastegate/boost control solenoid valve A and the PCM
    Open in the power supply circuit between the wastegate/boost control solenoid A and the PCM
    Short to power in the control circuit (power-controlled circuit) between the wastegate/boost control solenoid A and the PCM
    Wastegate/boost control solenoid valve A
    Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer, which could save you time and money during diagnosis.

Next, locate the “A” wastegate/boost control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for scratches, rubbing, exposed wires, burns, or melted plastic. Disconnect the connectors and carefully inspect the terminals (the metal parts) inside the connectors. Check if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic-bristled brush if terminal cleaning is necessary. Allow it to dry and apply electrical grease where the terminals make contact.

The most common failure is due to connection issues.

If you have a scan tool, clear the diagnostic codes from memory and see if P0246 returns. If it does not, the connections were likely your problem.

If the code returns, we will need to test the solenoid and its associated circuits. Typically, there are 2 wires to the wastegate/boost control solenoid. First, disconnect the wiring harness going to the wastegate/boost control solenoid. With a digital volt-ohm meter (DVOM), connect one meter lead to one terminal of the solenoid. Connect the remaining meter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance/0 ohms), replace the solenoid.

If this test passes, use a DVOM to ensure there is 12V on the wastegate/boost control solenoid power circuit (red lead to the solenoid power circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that is okay, check that the wastegate/boost control solenoid is properly grounded. Connect a test light to the 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the wastegate/boost control solenoid circuit ground. Using the scan tool to activate the wastegate/boost control solenoid, check if the test light illuminates each time the scan tool activates the solenoid valve. If the test light does not illuminate, it would indicate a circuit problem. If it lights up, wiggle the wiring harness going to the solenoid to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0246 code, it would most likely indicate a failing wastegate/boost control solenoid, although a faulty PCM cannot be ruled out until the solenoid has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to turbocharged and supercharged engines, including but not limited to some Audi, Ford, GM, Mercedes, Mitsubishi, VW, and Volvo vehicles.

The Powertrain Control Module (PCM) controls the boost pressure in a gasoline or diesel engine by managing the output circuit to the wastegate/boost pressure control solenoid valve “B”.

Whenever there is an electrical issue with this circuit that it cannot otherwise identify, the PCM will set the P0247 code. This code is considered an electrical circuit fault only.

Troubleshooting steps may vary depending on the manufacturer, the type of wastegate/boost pressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0247 engine code may include:

Malfunction Indicator Light (MIL) illuminated
Instrument cluster message alerting the driver to the condition
Lack of power

Causes

Possible causes for setting this code are as follows:

Open in the control circuit (ground circuit) between the wastegate/boost pressure control solenoid B and the PCM
Open in the power supply circuit between the wastegate/boost pressure control solenoid B and the PCM
Short to ground in the power supply circuit of the wastegate/boost pressure control solenoid B
Faulty wastegate/boost pressure control solenoid B
Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money during diagnosis.

Next, locate the wastegate/boost pressure control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for scratches, rubbing, exposed wires, burns, or melted plastic. Disconnect the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic-bristled brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from the memory and see if P0247 returns. If it does not, the connections were likely your problem.

If the code returns, we will need to test the solenoid and its associated circuits. Typically, there are 2 wires to the wastegate/boost pressure control solenoid. First, disconnect the wiring harness going to the wastegate/boost pressure control solenoid. With a digital volt ohm meter (DVOM), connect one meter lead to one terminal of the solenoid. Connect the remaining meter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance / 0 ohms), replace the solenoid.

If this test passes, with a DVOM, ensure you have 12V at the wastegate/boost pressure control solenoid power supply circuit (red lead to the solenoid power supply circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that is okay, check that the wastegate/boost pressure control solenoid is properly grounded. Connect a test light to the 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the wastegate/boost pressure control solenoid circuit ground. Using the scan tool to activate the wastegate/boost pressure control solenoid, check if the test light illuminates each time the scan tool activates the solenoid. If the test light does not illuminate, this would indicate a circuit problem. If it does illuminate, wiggle the wiring harness going to the solenoid to see if the test light flickers, indicating an intermittent connection.

If all tests have passed so far and you continue to get a P0247 code, this would most likely indicate a failing wastegate/boost pressure control solenoid, although a faulty PCM cannot be ruled out until the solenoid has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs must be programmed or calibrated to the vehicle to be installed correctly.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to turbocharged and supercharged engines, including but not limited to certain Ford, Mercedes, and Subaru vehicles.

The Powertrain Control Module (PCM) controls the boost pressure in a gasoline or diesel engine by managing the output circuit to the “B” wastegate/boost control solenoid.

Whenever there is an issue with the total boost range or engine performance that cannot be attributed to other circuit failures, the PCM will set the P0248 code. This code can indicate an electrical circuit fault or a mechanical engine problem, depending on the specific issue.

Troubleshooting steps may vary depending on the manufacturer, the type of wastegate/boost pressure control, and the color of the control solenoid wires.

Symptoms

Symptoms of a P0248 engine code may include:

    Malfunction indicator light illuminated
    Instrument cluster message alerting the driver to the condition
    Lack of power

Causes

Possible causes for this code being set include:

    Open in the control circuit (ground circuit) between the wastegate/boost control solenoid B and the PCM
    Open in the power supply circuit between the wastegate/boost control solenoid B and the PCM
    Short to ground in the power supply circuit of the wastegate/boost control solenoid B
    Short to power in the power supply circuit of the wastegate/boost control solenoid B
    Wastegate/boost pressure control solenoid B
    Possibly a failed PCM (highly unlikely)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer, which could save you time and money during diagnosis.

Next, locate the “B” wastegate/boost control solenoid on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for scratches, rubbing, exposed wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. Check if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if terminal cleaning is necessary. Allow it to dry and apply electrical grease where the terminals make contact.

The most common failure is due to electrical/vacuum connection issues.

If you have a scan tool, clear the diagnostic codes from memory and see if P0248 returns. If it doesn’t, the connections were likely your problem.

If the code returns, we will need to test the solenoid and its associated circuits. Typically, there are 2 wires to the wastegate/boost control solenoid. First, disconnect the wiring harness going to the wastegate/boost control solenoid. With a digital multimeter set to ohms (DVOM), connect one lead of the multimeter to one terminal of the solenoid. Connect the remaining multimeter lead to the other terminal of the solenoid. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the solenoid is open or shorted (infinite resistance or no resistance/0 ohms), replace the solenoid.

If this test passes, use a DVOM to ensure you have 12V at the power supply circuit of the wastegate/boost control solenoid (red lead to the solenoid power circuit, black lead to a good ground). Make sure the ignition is on. If there is no 12 volts at the solenoid, or if there is 12 volts when the ignition is off, repair the wiring from the PCM or relay to the solenoid, or possibly a faulty PCM.

If that checks out, verify that the wastegate/boost control solenoid is properly grounded. Connect a test light to the 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the wastegate/boost control solenoid circuit ground. Using the scan tool to activate the wastegate/boost control solenoid, check if the test light illuminates each time the scan tool activates the solenoid. If the test light does not illuminate, it would indicate a circuit problem. If it does light up, wiggle the wiring harness going to the solenoid to see if the test light flickers, indicating an intermittent connection.

Ensure all mechanical components are secured and functioning properly. Make sure that if vacuum is used, there is sufficient vacuum at the wastegate/boost control solenoid. Otherwise, locate the source of the vacuum blockage or leak.

If all tests have passed so far and you continue to get a P0248 code, it would most likely indicate a faulty wastegate/boost control solenoid, although a defective PCM cannot be ruled out until the solenoid has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.

What Does It Mean?

This generic powertrain diagnostic trouble code (DTC) generally applies to all OBD-II equipped vehicles with a supercharger air cooler. This may include, but is not limited to, vehicles from Ford, Chevy, Mazda, Toyota, etc.

In forced induction systems, they use a supercharger air cooler or what I will call an intercooler (IC) to help cool the supercharged air used by the engine. These operate similarly to a radiator.

In the case of the IC, instead of cooling antifreeze, it cools the air to produce a more efficient air/fuel mixture, which in turn leads to better fuel economy, improved performance, etc. The IC is part of the supercharger pressure side of the induction system. The bypass valve is used, as its name implies, to allow air to bypass the intercooler to be vented to the atmosphere and/or recirculated. The Engine Control Module (ECM) uses it to adjust the valve based on current engine conditions and needs.

The ECM illuminates the Check Engine light with P024A and related codes when it monitors a condition outside a specified range in the intercooler bypass control circuit and/or system. This code can be triggered by a mechanical and/or electrical fault. If I had to guess here, I would lean towards a mechanical issue likely being the problem. That being said, either is possible.

P024A Supercharger Air Cooler Bypass Control Circuit Range/Performance code is set when the ECM detects an abnormal range and/or performance of the valve itself and/or the circuit.
How severe is this DTC?

The severity in this case would be moderate. You do not want to leave this issue unattended as it could evolve into something much more serious fairly quickly. Keep in mind that problems do not improve over time unless corrected. Engine damage is expensive, almost every time, so if you have exhausted your abilities, take the vehicle to a reputable repair center.
What are some of the symptoms of the code?

Symptoms of a P024A engine code may include:

Poor engine performance
Vehicle entering “limp mode”
Engine misfire
Poor fuel consumption

What are some common causes of the code?

Causes

of this code may include:

Bypass valve stuck open/closed
Obstruction in the operational movement range of the bypass valve
Broken or damaged wiring harness
Faulty fuse/relay
ECM problem
Pin/connector issue. (e.g., corrosion, broken locking tab, etc.)

What are the P024A troubleshooting steps?

Be sure to check the Technical Service Bulletins (TSBs) for your vehicle. Accessing a known fix can save you time and money during diagnosis.
Tools

When working on the forced induction system, you may need:

OBD code reader
Hose clamp pliers
Lubricant
Multimeter
Basic socket set
Ratchet and wrench sets
Basic screwdriver set
Rags/shop towels
Battery terminal cleaner
Service manual

Safety Tips

Let the engine cool down
Chock the wheels
Wear PPE (Personal Protective Equipment)

NOTE: ALWAYS check and record your battery and charging system integrity before proceeding with troubleshooting.
Basic Step #1

Locate your supercharger air cooler bypass control valve by following the charge piping going to your intercooler (IC); it may be mounted directly on the charge pipe. Depending on your specific make and model, you may find your IC mounted in your front bumper, front fenders, or perhaps directly under the hood among many other possible locations. Once the valve is located, inspect for any obvious physical damage.

NOTE: Ensure the engine is off.
Basic Step #2

It may be straightforward to remove the valve from the vehicle entirely to check its functionality. Especially recommended if the P024B code is active. Once removed, inspect for any obstruction in the valve’s range of movement. If possible, clean the valve before reinstalling it.

NOTE: Always refer to the service manual first, as this may not be possible or recommended for your specific vehicle.
Basic Tip #3

The bypass valve harness may be routed through areas exposed to the elements. These areas should be closely inspected for nicks, cuts, signs of corrosion, etc., in the wires involved in the circuit.

NOTE: Ensure the battery is disconnected before performing any electrical repairs.
Basic Step #4

Depending on your scan tool, you can check the valve’s functionality by controlling it and observing its range of movement. If accessible, you can disconnect one end of the valve to see the moving parts. Using your scan tool, fully open and close the valve while observing the mechanical operation of the valve itself. If you notice the valve sticking and nothing is obstructing it, the valve is likely faulty. In this case, you can try replacing it. Ensure the manufacturer also recommends a new valve in this scenario. Refer to the manual.
Basic Step #5

You will want to rule out any electrical issues in the involved harness. To do this, you may need to disconnect it at both the valve and the ECM. Using your multimeter, check the circuit’s integrity by performing many basic electrical tests (i.e., continuity). If everything checks out, there may be input tests you could perform involving testing the connector at the valve to verify ECM functionality with the valve.

What does it mean?

This generic powertrain diagnostic trouble code (DTC) generally applies to all OBD-II equipped vehicles with a supercharger air cooler. This may include, but is not limited to, vehicles from Ford, Chevy, Mazda, Toyota, etc.

In forced induction systems, they use a supercharger air cooler or what I will call an intercooler (IC) to help cool the boosted air used by the engine. These operate similarly to a radiator.

In the case of the IC, instead of cooling antifreeze, it cools the air to produce a more efficient air/fuel mixture, which in turn leads to better fuel economy, better performance, etc. The IC is part of the boost pressure side of the induction system. The bypass valve is used, as its name implies, to let air bypass the intercooler to be vented to the atmosphere and/or recirculated. The Engine Control Module (ECM) uses it to adjust the valve based on current engine conditions and needs.

The ECM illuminates the Check Engine light with P024B and related codes when it monitors a condition outside a specific range in the intercooler bypass control circuit and/or system. This code can be triggered by a mechanical and/or electrical fault. If I had to guess here, I would lean towards a mechanical issue likely being the problem. That being said, either is possible.

P024B Supercharger Air Cooler Bypass Control Circuit Stuck code is set when the ECM detects that the valve is stuck and can no longer control it electronically.
How severe is this DTC?

The severity in this case would be moderate. You do not want to leave this issue unattended as it could evolve into something much more serious fairly quickly. Keep in mind that problems do not improve over time unless fixed. Engine damage is expensive, almost every time, so if you have exhausted your abilities, take the vehicle to a reputable repair center.
What are some of the symptoms of the code?

Symptoms of a P024B engine code may include:

Poor engine performance
Vehicle entering “limp mode”
Engine misfire
Poor fuel economy

What are some of the common causes of the code?

Causes

of this code may include:

Bypass valve stuck open/closed
Obstruction in the operational movement range of the bypass valve
Broken or damaged wiring harness
Faulty fuse/relay
ECM problem
Pin/connector issue. (e.g., corrosion, broken locking tab, etc.)

What are the P024B troubleshooting steps?

Be sure to check the Technical Service Bulletins (TSBs) for your vehicle. Access to a known fix can save you time and money during diagnosis.
Tools

When working on the forced induction system, you may need:

OBD code reader
Hose clamp pliers
Lubricant
Multimeter
Basic socket set
Ratchet and wrench sets
Basic screwdriver set
Rags/shop towels
Battery terminal cleaner
Service manual

Safety Tips

Let the engine cool down
Chock the wheels
Wear PPE (Personal Protective Equipment)

NOTE: ALWAYS check and record the integrity of your battery and charging system before proceeding with troubleshooting.
Basic Step #1

Locate your supercharger air cooler bypass control valve by following the charge piping going to your intercooler (IC); it may be mounted directly on the charge pipe. Depending on your specific make and model, you might find your IC mounted in your front bumper, front fenders, or perhaps directly under the hood among many other possible locations. Once the valve is located, inspect for any obvious physical damage.

NOTE: Ensure the engine is off.
Basic Step #2

It may be straightforward to remove the valve from the vehicle completely to check its functionality. Particularly recommended if the P024B code is active. Once removed, inspect for any obstruction in the valve’s range of motion. If possible, clean the valve before reinstalling it.

NOTE: Always refer to the service manual first, as this may not be possible or recommended on your specific vehicle.
Basic Tip #3

The bypass valve harness may be routed through areas exposed to the elements. These areas should be closely inspected for nicks, cuts, signs of corrosion, etc., in the wires involved in the circuit.

NOTE: Ensure the battery is disconnected before performing any electrical repairs.
Basic Step #4

Depending on your scan tool, you can check the valve’s functionality by commanding it and observing its range of motion. If accessible, you can disconnect one end of the valve to see the moving parts. Using your scan tool, fully open and close the valve while observing the mechanical operation of the valve itself. If you notice the valve sticking and nothing is obstructing it, the valve is likely faulty. In this case, you can try replacing it. Ensure the manufacturer also recommends a new valve in this scenario. Refer to the manual.
Basic Step #5

You will want to rule out any electrical issues in the involved harness. To do this, you may need to disconnect it at both the valve and the ECM. Using your multimeter, check the circuit’s integrity by performing many basic electrical tests (i.e., continuity). If everything checks out, there may be input tests you could perform involving testing the connector at the valve to verify ECM functionality with the valve.