A wastegate solenoid can click on command and still fail to control boost properly. A P0248 code means the engine computer saw that wastegate solenoid B is not giving the boost result it commanded.
This guide explains how boost control is checked, why hoses and stuck wastegates cause this code and how to fix it.
P0248 Code Breakdown
Every OBD-II code follows the same five-character pattern set by the SAE J2012 standard. Each character narrows down which system has the fault. This table shows what each part of the code tells you.
| Character | Meaning | What It Tells You |
|---|---|---|
| P | Powertrain | The fault is in the engine or transmission systems. |
| 0 | Generic (SAE) code | The definition is the same on every OBD-II vehicle. |
| 2 | Fuel and air metering | The fault involves fuel and air metering, such as injectors, the fuel pump, throttle sensors or boost control. |
| 48 | Specific fault | Turbocharger Wastegate Solenoid B Range/Performance |
What the P0248 Code Means
The SAE J2012 standard defines the P0248 code as Turbocharger Wastegate Solenoid B Range/Performance. Wastegate solenoid B is a second boost control solenoid. It is used on some twin turbo engines, with one solenoid per turbo, and on engines with more than one stage of boost control. Check your service manual to see which turbo it controls.
The powertrain control module (PCM) pulses the solenoid on and off many times per second. By changing the on-time, it changes how much pressure reaches the wastegate actuator, which sets how far the wastegate opens and how much boost the turbo makes.
Some newer engines use an electric wastegate actuator with its own position sensor instead of a solenoid and hoses. On those, the same codes can point to the actuator motor or its circuit.
Range/performance means the circuit is electrically intact, but the wastegate solenoid B is not doing what the PCM commands. The PCM sees that the result, such as a pressure, position or flow, does not follow its command closely enough.
Symptoms of a Bad Wastegate Solenoid B
Boost control problems usually show up as power problems. Common signs of a P0248 code include:
- Check engine light on
- Low boost and sluggish acceleration
- Overboost surges followed by reduced power
- Limp mode
- Boost gauge that reads lower or higher than normal
- Whistling or hissing from a cracked hose
A solenoid that fails with no power usually leaves the wastegate at its spring setting, which gives low base boost. A solenoid that sticks or a hose that falls off can cause either low boost or overboost, depending on the design.
What Causes the P0248 Code?
Range codes often come from mechanical problems, not wiring:
- Cracked or disconnected hoses. The solenoid cannot deliver its signal to the actuator.
- Sticking wastegate or actuator. The flap does not move as commanded.
- Solenoid sticking inside. Dirt or oil stops it from switching.
- Boost leak. Real boost stays low no matter what the solenoid does.
- Faulty boost sensor. The PCM sees the wrong result.
Tools You Will Need
You can do most of this testing at home with basic tools:
- OBD-II scan tool that shows boost and solenoid duty cycle
- Digital multimeter and test light
- Hand vacuum and pressure pump
- Hose routing diagram for your engine
- Replacement silicone or rubber hose
Step-By-Step Diagnosis of the P0248 Code
Start with the hoses and connector, since they fail more often than the solenoid itself.
Check Live Data and Command the Part
With the engine running, look at the wastegate solenoid B duty cycle along with desired and actual boost. If your scan tool can command the solenoid, turn it on and off and listen for a click.
Inspect the Hoses
Trace every hose between the turbo outlet, the solenoid and the wastegate actuator. Look for cracks, splits, soft spots and hoses on the wrong ports. Compare with the routing diagram on the underhood label or in the service manual.
Check the Actuator and Wastegate
With the engine off, apply pressure or vacuum to the actuator as your service manual describes. The rod should move smoothly and hold. Make sure the wastegate arm moves freely by hand.
Test the Solenoid Ports
Remove the solenoid and blow gently through its ports with it unpowered, then with 12 volts applied through a fused jumper. Air should flow through different ports in each state, as your service manual describes. A solenoid that does not switch, or leaks in both states, is sticking inside.
Compare Desired and Actual Boost
During a brief, safe acceleration, watch desired boost, actual boost and solenoid duty cycle. If the duty cycle rises but boost does not follow, look for a hose, wastegate or leak problem. If boost overshoots the target, the wastegate may not be getting its signal.
How to Fix the P0248 Code
Match the repair to what your tests found. Then clear the code and drive under the same conditions that set it.
- Replace cracked or loose hoses and route them as the diagram shows.
- Repair the connector or wiring
- Replace wastegate solenoid B if its resistance is out of range or it sticks.
- Free or repair a sticking wastegate or actuator.
- Fix boost leaks in the intake and intercooler piping.
After any repair, clear the codes and road test while watching desired and actual boost. Boost should rise quickly to the target and settle there without spiking or falling short.
Common Mistakes to Avoid
These mistakes waste money or leave the real fault in place:
- Assuming a range code always means a bad part
- Skipping the mechanical checks that make a good part look bad
- Routing hoses to the wrong solenoid ports after replacement
- Replacing the turbo when a hose or solenoid is the cause
What Repairs Cost
The cost to fix a P0248 code depends on the cause. This table shows typical ranges for parts and labor.
| Repair | DIY Cost | Typical Shop Cost |
|---|---|---|
| Vacuum or pressure hose | $5 to $30 | $75 to $150 |
| Connector or wiring repair | $10 to $40 | $100 to $300 |
| Wastegate or boost control solenoid | $30 to $150 | $150 to $350 |
| Wastegate actuator | $80 to $400 | $300 to $900 |
Solenoid and hose repairs are usually quick, since the solenoid often sits on the inner fender or near the turbo intake. Actuator replacement costs more because it may need the turbo heat shield or more parts removed.
Can You Drive with a P0248 Code?
You can usually drive gently. Low boost makes the engine slow but is not harmful on its own.
If the fault causes overboost surges, avoid full throttle. Too much boost can damage the engine, and the PCM may cut power suddenly, which can be dangerous in traffic.
Related Codes
These codes often show up with this one or point to the same system:
| Code | Meaning |
|---|---|
| P0247 | Turbocharger Wastegate Solenoid B Malfunction |
| P0249 | Turbocharger Wastegate Solenoid B Low |
| P0250 | Turbocharger Wastegate Solenoid B High |
| P0234 | Turbo/Super Charger Overboost Condition |
| P0299 | Turbo/Super Charger A Underboost Condition |
Fixing Wastegate Solenoid B
A P0248 code means wastegate solenoid B is not giving the boost the PCM commands. Cracked hoses, sticking wastegates and boost leaks cause most cases.
- Inspect every hose for cracks and wrong routing.
- Check the actuator and wastegate movement.
- Pressure test for boost leaks.
- Replace the solenoid if it sticks.
Frequently Asked Questions
Does the P0248 Code Mean the Turbo Is Bad?
Usually not. Range codes more often come from hoses, a sticking wastegate arm or a boost leak. The turbo itself is the last thing to replace, and only after the cheaper parts check out.
Where Is the Wastegate Solenoid?
It is usually mounted near the turbo, on the inner fender or on the intake piping, with two or three small hoses attached. On some diesels it controls vacuum instead of boost pressure. Your service manual shows the exact location.
What Is the N75 Valve?
N75 is Volkswagen and Audi’s name for the boost control solenoid on many turbo engines. It controls the pressure or vacuum that operates the wastegate or turbo vanes. A failing N75 is a common cause of low boost on those engines.
Why Does My Boost Spike and Then Cut Out?
A spike followed by a sudden loss of power usually means boost rose past the limit and the PCM cut power to protect the engine. A wastegate that does not get its control signal, from a failed solenoid or a split hose, is a common cause.
Can I Drive Without the Wastegate Solenoid?
The engine will usually run, but boost control will be poor. Without the solenoid, many engines stay at low spring boost, and some may overboost. Replace it soon to bring back normal power and protect the engine.