P0048 is a turbocharger/supercharger boost control code that can leave you with low power, strange noises, and a glowing check engine light. The good news is this code is usually very fixable once you track down whether the problem is electrical, mechanical, or both. In this guide, you’ll learn what P0048 actually means, the most common causes, symptoms to watch for, how a technician would diagnose it, and what repairs typically cost. That way you can talk confidently with your shop or decide if it’s a DIY job.
What Does P0048 Mean?
P0048 is defined as “Turbocharger/Supercharger Boost Control Solenoid ‘A’ Circuit High.” In plain language, your engine control unit (ECU) is seeing higher-than-expected voltage or signal in the electrical circuit that controls boost pressure for the turbo or supercharger.
This usually points to an electrical issue affecting the boost control solenoid or valve: damaged wiring, a short to power, a faulty solenoid, or sometimes a problem inside the ECU. Because this solenoid helps regulate boost, you can end up with either low power, overboost, or erratic performance depending on how the system fails.
Quick Reference
- Code: P0048 – Turbocharger/Supercharger Boost Control Solenoid “A” Circuit High
- Severity: Moderate to high – can affect drivability and engine safety
- Common causes: Wiring short, faulty boost control solenoid, bad connector, ECU driver fault
- Typical symptoms: Low power, limp mode, check engine light, possible overboost
- First checks: Visual wiring inspection, scan live data, test solenoid resistance and power/ground
Real-World Example / Field Notes
One case that sticks in my mind was a diesel pickup that came in with P0048, low power, and a complaint that “it sounds like the turbo is angry.” The owner had already replaced the turbocharger at another shop with no improvement. A quick visual inspection showed the boost control solenoid harness had rubbed through on a bracket and was shorted to 12V. The ECU saw a constant high signal, set P0048, and forced the truck into a low-boost strategy. A short length of new wiring, proper routing, and a secured harness fixed the issue for a fraction of the cost of that unnecessary turbo replacement.
Symptoms of P0048
- Check engine light on – Often the only initial sign, especially on newer vehicles.
- Low power / sluggish acceleration – Turbo may not build proper boost, or ECU limits power.
- Limp mode – Vehicle may restrict throttle and RPM to protect the engine.
- Overboost or surging – In some failures, you might feel sudden spikes in power or jerky acceleration.
- Poor fuel economy – Incorrect boost control can make the engine run inefficiently.
- Whistling or whooshing noises – You may hear abnormal turbo sounds if boost is not managed correctly.
- Black smoke (diesels) – Excess fuel with improper boost can cause heavy exhaust smoke.
- Other boost-related codes – Codes like P0234 (overboost) or P0299 (underboost) may appear along with P0048.
Common Causes of P0048
Most Common Causes
- Shorted wiring to the boost control solenoid “A” – Chafed or melted wires touching battery voltage or another power source will drive the circuit high.
- Faulty boost control solenoid/valve – Internal short or low resistance can cause excessive current and a high signal reading.
- Corroded or damaged connector – Moisture intrusion or loose pins can create erratic high-voltage signals.
- Incorrect aftermarket wiring or tuning – Poorly installed boost controllers or piggyback modules can interfere with the factory circuit.
- Harness damage near the turbo – Heat and vibration around the turbocharger area often break insulation and wiring.
Less Common Causes
- ECU driver failure – The transistor inside the ECU that controls the solenoid can short internally, keeping the circuit high.
- Short to power elsewhere in the harness – A harness pinch or previous repair may tie the solenoid circuit into another powered circuit.
- Water intrusion into harness – On some trucks and SUVs, water can wick through loom and cause intermittent shorts.
- Wrong solenoid installed – Using an incorrect part number with different resistance can confuse the ECU and trigger P0048.
- Severe internal turbo actuator fault – On some integrated electronic actuators, an internal short can set this code.
Diagnosis: Step-by-Step Guide
To diagnose P0048 properly, you’ll want a decent scan tool (preferably one that can read live data and Mode $06), a digital multimeter, basic hand tools, and wiring diagrams for your specific vehicle. A test light and back-probe pins also make life easier. If you’re not comfortable checking circuits, this is a good time to involve a qualified shop, because guessing with boost systems can get expensive.
- Verify the code and record freeze-frame data. Connect your scan tool, confirm P0048, and note RPM, load, boost pressure, and vehicle speed when the code set. This helps you reproduce the condition later.
- Check for related codes. Look for codes like P0234, P0299, or other boost/voltage codes. Multiple codes can point you toward a shared wiring issue or ECU problem.
- Perform a visual inspection. With the engine off, inspect the wiring and connector at the turbo/supercharger boost control solenoid “A.” Look for melted insulation, rubbed-through sections, broken clips, or green corrosion on terminals.
- Check solenoid power and ground. Using a multimeter or test light, verify you have proper power and ground at the solenoid connector with the key on. Compare readings to your wiring diagram and specifications.
- Measure solenoid resistance. Disconnect the solenoid and measure resistance across its terminals. A reading far outside factory spec (often just a few ohms) indicates an internal short or open circuit.
- Test for short to power. With the solenoid unplugged, check the signal/control wire to see if it has 12V when it shouldn’t. Wiggle the harness while watching the meter to catch intermittent shorts.
- Use live data to monitor command vs. actual. On many vehicles you can view “boost control duty cycle” or similar data. Compare ECU command to actual boost and solenoid behavior while driving or during a controlled test.
- Inspect harness routing and previous repairs. Look for tape-wrapped sections, butt connectors, or aftermarket add-ons near the boost control wiring. Poor repairs often hide in these spots.
- Check Mode $06 (if available). Some scan tools let you see test results for the boost control circuit. This can show if the failure is intermittent or constant.
- Evaluate ECU only after other checks. If wiring, connectors, and the solenoid all test good but the circuit still shows high with the ECU connected, you may have an internal ECU driver fault that requires professional testing or replacement.
Pro tip: Don’t condemn the turbocharger itself just because you have P0048 and low power. This code is about the control circuit, not the turbo’s mechanical health. Always prove the electrical side first.
Possible Fixes & Repair Costs
Repairs for P0048 range from simple wiring fixes to more involved component replacement. The exact cost depends on your vehicle, parts prices, and labor rates in your area.
- Repair or replace damaged wiring/connector – Splicing in new wire, replacing terminals, and rerouting the harness away from heat or sharp edges. Typical cost: $100–$300 depending on access and severity.
- Replace boost control solenoid/valve – Common on high-mileage or heat-soaked vehicles. Typical cost: $150–$450 parts and labor, depending on brand and location.
- Replace integrated electronic turbo actuator – On some modern turbos, the actuator and solenoid are one unit. Typical cost: $400–$1,200+ installed.
- Correct aftermarket wiring or tuning issues – Removing or reconfiguring piggyback controllers or poorly installed boost gauges/controllers. Typical cost: $100–$400, depending on complexity.
- ECU repair or replacement – Least common but possible. Typical cost: $600–$1,500+ including programming.
In general, most P0048 issues end up on the lower end of that range if caught early and limited to wiring or solenoid replacement. Costs climb when access is difficult (tight engine bays, turbo buried behind the engine) or when integrated actuators or the ECU are involved.
Can I Still Drive With P0048?
You can usually drive short distances with P0048, but it’s not something you want to ignore. Many vehicles will enter a reduced-power or limp mode to protect the engine, which means poor acceleration and limited speed. In some cases, if the system allows overboost, you risk engine damage, head gasket issues, or turbo failure. If you notice severe loss of power, loud turbo noises, or heavy smoke, you should avoid highway driving and have the vehicle inspected as soon as possible.
What Happens If You Ignore P0048?
Ignoring P0048 can lead to more than just an annoying check engine light. Long-term driving with improper boost control can stress the turbocharger, increase exhaust gas temperatures, and potentially damage pistons, valves, or the catalytic converter. You may also end up with poor fuel economy and additional fault codes as the ECU struggles to manage air/fuel ratios. Fixing the root cause early is almost always cheaper than waiting for secondary damage to show up.
Related Codes
- P0027 – Exhaust Valve Control Solenoid Circuit Range/Performance Bank 1
- P0026 – Intake Valve Control Solenoid Circuit Range/Performance Bank 1
- P0019 – Crankshaft Position Camshaft Position Correlation Bank 2 Sensor B
- P0018 – Crankshaft Position Camshaft Position Correlation Bank 2 Sensor A
- P0017 – Crankshaft Position Camshaft Position Correlation Bank 1 Sensor B
- P0016 – Crankshaft Position Camshaft Position Correlation Bank 1 Sensor A
- P0009 – Engine Position System Performance Bank 2
- P0008 – Engine Position System Performance Bank 1
- P0007 – Fuel Shutoff Valve “A” Control Circuit High
- P0006 – Fuel Shutoff Valve “A” Control Circuit Low
Key Takeaways
- P0048 points to a high-voltage issue in the turbo/supercharger boost control solenoid “A” circuit, not automatically a bad turbo.
- Common causes include shorted wiring, faulty solenoids, damaged connectors, and occasionally ECU driver faults.
- Symptoms range from a simple check engine light to limp mode, low power, and possible overboost conditions.
- Diagnosis requires a scan tool, multimeter, and careful inspection of wiring and solenoid operation.
- Most repairs fall in the $100–$450 range when limited to wiring or solenoid replacement; more complex issues can cost more.
- Driving for long with P0048 can risk turbo and engine damage, so it’s best to address the problem promptly.
Vehicles Commonly Affected by P0048
P0048 shows up most often on turbocharged vehicles, especially modern diesel trucks and smaller turbo gas engines. You’ll commonly see this code on:
- Ford – Power Stroke diesels (6.0L, 6.4L, 6.7L) and EcoBoost gasoline engines.
- Chevrolet/GMC – Duramax diesels and turbocharged gasoline models.
- Dodge/Ram – Cummins diesel trucks and some turbo gas applications.
- Volkswagen/Audi – TDI diesels and TSI/TFSI turbo gasoline engines.
- Subaru – WRX, STI, and other turbo boxer engines.
- Hyundai/Kia – GDI turbo engines in sedans and SUVs.
Any turbocharged or supercharged vehicle with electronic boost control can set P0048, so always check your specific service information and wiring diagrams.
FAQ
Can I clear P0048 and keep driving if the car feels fine?
You can clear the code, but if the underlying issue is still there, P0048 will usually return. Even if the car feels okay now, an electrical fault in the boost control circuit can worsen over time. It’s better to diagnose and repair the cause rather than repeatedly clearing the code.
Is P0048 always caused by a bad turbocharger?
No. P0048 is an electrical circuit code for the boost control solenoid “A,” not a direct turbo mechanical failure code. While a failing actuator attached to the turbo can sometimes be involved, most fixes involve wiring, connectors, or the solenoid itself, not replacing the entire turbo.
How serious is P0048 for my engine?
P0048 is moderately to highly serious because it affects how your engine controls boost. In many cases the ECU will limit power to protect the engine, but if the system allows overboost, you could risk internal engine damage or turbo failure. It’s not an emergency tow situation in most cases, but you shouldn’t ignore it.
Can a bad tune or aftermarket boost controller cause P0048?
Yes. Aggressive tuning, piggyback modules, or poorly installed manual/electronic boost controllers can interfere with the factory boost control circuit. The ECU may see abnormal voltage or duty cycle and set P0048. If the code appeared right after modifications, that’s the first place to look.
Does P0048 always require an ECU replacement if wiring looks good?
Not always. Before blaming the ECU, you should load-test the wiring, verify grounds, and confirm the solenoid’s resistance and operation. Some issues only show up under load or heat. ECU failure is possible but relatively rare compared to wiring or solenoid faults, so it should be the last item on the list after all other checks pass.