The OBD2 code P0048 refers to “Turbo/Supercharger Boost Control A Circuit High,” indicating that the electrical circuit connected to the turbocharger or supercharger boost control is receiving a voltage higher than expected.
This code can cause various symptoms, including intermittent power loss, erratic engine performance, or even engine stalling at high speeds. It typically points towards an electrical issue within the boost control system, such as a faulty component, wiring problem, or a bad connection.
P0048 quick overview
| Meaning | P0048: Turbo/Supercharger Boost Control A Circuit High |
| Is it serious? | Yes, this code can significantly affect the vehicle’s performance and drivability. |
| Possible causes | – Damaged or corroded wiring and connectors – Faulty boost control solenoid – Improper wastegate actuator function – Excessive voltage supply to the boost control solenoid – Issues with vacuum levels in the turbo system |
| How to diagnose? | Inspect the wiring harness for signs of damage or corrosion that might cause high circuit voltage. Check the boost control solenoid for proper operation, ensuring it is not stuck open or closed. Test the wastegate actuator to confirm it functions correctly, allowing for proper turbo boost control. Verify the voltage supply to the boost control solenoid is within the specified range. Ensure correct vacuum levels in the turbocharger system, which are crucial for optimal turbo performance. |
P0048 Meaning
The P0048 error code signals a problem with the electrical system that controls how much boost your turbo or supercharger is supposed to give your engine. If this system sends too much electricity (a “high circuit”), it can mess up the balance, leading to power loss or unpredictable engine behavior.
This could be due to something simple like a loose wire or something more complicated like a faulty part in the boost control system. Mechanics will look over the electrical connections and components, like the solenoid that helps regulate boost, to find and fix the issue.
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How to fix P0048 – learn from mechanics
I looked into P0048 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Volkswagen P0048
Vehicle information 2010 Volkswagen Golf GTI 2.0L Turbo
Issue + repair history
- MIL lamp illuminated
- Engine experiencing intermittent power loss
- Code P0048: Turbo/Supercharger Boost Control A Circuit High
- Previous repair: Replaced boost pressure sensor
- Symptoms persist despite sensor replacement
Other OBD2 Codes + Test Results
- P0048: Turbo/Supercharger Boost Control A Circuit High
Mechanic suggestions
- Inspect wiring harness for any signs of damage or corrosion
- Check boost control solenoid for proper operation
- Test wastegate actuator for proper function
- Verify proper voltage supply to boost control solenoid
- Ensure proper vacuum levels in the turbocharger system
Final fix
- Discovered loose connection at the boost control solenoid
- Repaired connection and cleared code, resolving the issue
Case #2: Ford P0048
Vehicle information 2012 Ford Focus ST 2.0L Turbo
Issue + repair history
- Check engine light illuminated
- Engine performance feels erratic
- Code P0048: Turbo/Supercharger Boost Control A Circuit High
- Previous repair: Replaced turbo wastegate actuator
- Symptoms persist despite actuator replacement
Other OBD2 Codes + Test Results
- P0048: Turbo/Supercharger Boost Control A Circuit High
Mechanic suggestions
- Inspect wiring harness for any signs of damage or corrosion
- Check boost control solenoid for proper operation
- Test wastegate actuator for proper function
- Verify proper voltage supply to boost control solenoid
- Ensure proper vacuum levels in the turbocharger system
Final fix
- Identified damaged wiring at the boost control solenoid connector
- Repaired wiring and cleared code, resolving the issue
Case #3: Ford P0048
Vehicle information 2014 BMW 335i 3.0L Turbo
Issue + repair history
- MIL lamp on constantly
- Engine stalling at high speeds intermittently
- Code P0048: Turbo/Supercharger Boost Control A Circuit High
- Previous repair: Replaced turbocharger wastegate
- Symptoms persist despite wastegate replacement
Other OBD2 Codes + Test Results
- P0048: Turbo/Supercharger Boost Control A Circuit High
Mechanic suggestions
- Inspect wiring harness for any signs of damage or corrosion
- Check boost control solenoid for proper operation
- Test wastegate actuator for proper function
- Verify proper voltage supply to boost control solenoid
- Ensure proper vacuum levels in the turbocharger system
Final fix
- Discovered faulty boost control solenoid
- Replaced solenoid and cleared code, resolving the issue
How to diagnose P0048
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Explanation |
|---|---|
| Inspect the wiring harness | Look for damage or corrosion that could cause an unexpectedly high voltage in the circuit. |
| Check the boost control solenoid | Ensure it operates correctly, as a faulty solenoid can lead to high circuit issues. |
| Test the wastegate actuator | Confirm its proper operation, which is critical for managing turbo boost levels. |
| Verify the voltage supply | Check that the voltage to the boost control solenoid is within the vehicle manufacturer’s specifications. |
| Ensure proper vacuum levels | Verify that the vacuum system is functioning correctly to maintain optimal turbo performance. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko