P0249 Wastegate solenoid: signal or voltage too low ("B")

By: Diagno editorial team · Updated: 2026-10-15

P0249 means: Wastegate solenoid: signal or voltage too low ("B"). The turbo pushes extra air into the engine. Drive gently and have the car checked soon. The repair usually costs about €60–300 in Estonia. The most common cause: connector loose, damp or corroded. Other possible causes: wire broken or shorted to ground, faulty sensor or actuator.

What it means

The turbo pushes extra air into the engine. The computer found the boost pressure wrong or the turbo control not working. The car often goes into limp mode. The signal voltage is too low. Usually a wire is broken, a connector is loose or a wire is shorted to ground.

What you may notice

• Much less power (limp mode)
• Turbo whistling or hissing
• Black smoke
• Engine light on

What could be wrong

1. 1Connector loose, damp or corroded
2. 2Wire broken or shorted to ground
3. 3Faulty sensor or actuator
4. 4Engine computer fault (rare)

Repair difficulty: Hard

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? Check the boost hoses, especially the joints and around the intercooler. An oily hose points to a leak. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the sensor or actuator

Standard SAE description: Turbocharger Wastegate Solenoid B Low