P0249 Turbocharger/Supercharger Wastegate Solenoid B Low

P0249 indicates wastegate solenoid B circuit low. The B control signal is grounded, missing voltage, or below expected electrical range.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not adjust the wastegate before repairing the low solenoid B control circuit.

Symptoms of P0249

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0249

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Measure solenoid B control voltage, feed, ground, resistance, and current while checking for short-to-ground faults.
Inspect harness routing near turbo heat, connector terminals, solenoid wiring, fuse supply, and module driver output.
Compare low circuit behavior with desired boost, actual boost, actuator position, and freeze-frame load or RPM.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.