What it means
The control circuit for wastegate solenoid B reports a voltage above the expected range. Typical causes are a short to power or an open ground.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Wastegate solenoid B helps control boost by changing the wastegate actuator’s operation. The control module monitors the B circuit and sets P0248 when its voltage is higher than expected, which may indicate a short to power or an open ground path.
Common causes
Most likely first.
- Wastegate solenoid B defective
- Wiring shorted to power
- Ground circuit open
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
How to diagnose it
- Record freeze-frame data and check for companion boost-control codes before clearing the fault.
- Inspect solenoid B’s connector, wiring, and ground path for damage, corrosion, loose terminals, or contact with a power source.
- Use the wiring diagram to test the B circuit for a short to power and compare results with the manufacturer’s specification.
- Check continuity through the solenoid B ground path and test the solenoid winding for an open or fault.
- If the solenoid and wiring pass, use the manufacturer’s procedure to verify the control-module output.
Common fixes
- Repair an open ground in the wastegate solenoid B circuit.
- Repair wiring shorted to power and secure it against further chafing.
- Clean or repair damaged solenoid B connector terminals.
- Replace wastegate solenoid B if it fails the specified electrical or functional test.
- Repair the control module only if its output is confirmed faulty.
Can I keep driving?
Limit acceleration and avoid towing or other high-load driving because boost control may be impaired and power may drop. Stop if smoke is heavy or the vehicle cannot maintain safe speed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.