What causes fault code P0249?

• Most likely: Short to ground in the wiring harness for solenoid B • Likely: Faulty wastegate solenoid (internal short/open) • Possible: High resistance or corrosion in the electrical connector • Rare: Faulty Engine Control Module (ECM/ECU) internal driver failure

Powertrain (Engine & Gearbox)Standard EOBD

P0249 - Turbocharger Wastegate Solenoid B Low

Q: What are the symptoms of fault code P0249?

• Check Engine Light (MIL) illumination • Significant loss of engine power (Limp mode) • Unusual noises from the turbocharger area • Hesitation or surging during acceleration • Failed emissions test due to stored fault code

Q: How do you fix fault code P0249?

STEP 1: Inspect the electrical connector at solenoid B for corrosion or backed-out pins. Clean and secure as necessary. STEP 2: Measure the solenoid's internal resistance using a multimeter. Normal values are typically 10-30 Ohms (refer to OEM specs). Infinite resistance indicates an open circuit. STEP 3: Check for 12V supply at the solenoid connector with ignition ON. Also check continuity of the signal wire back to the ECU to rule out a short to ground. STEP 4: Use an oscilloscope or scan tool active command to verify the PWM (Duty-cycle) signal from the ECU. If signal is missing despite good wiring, the ECU driver may be faulty. STEP 5: If the solenoid is found to be defective, replace the component and perform a drive cycle to clear the code.

Last updated:1 February 2026

Related:Wastegate, Turbocharger, Engine Control Unit (ECU), Wiring harness, Boost pressure sensor

System

Powertrain (Engine & Gearbox)

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Technical Description

P0249 is a generic OBD-II diagnostic trouble code indicating that the Engine Control Unit (ECU) has detected an unexpectedly low voltage condition in the circuit for turbocharger wastegate control solenoid 'B'. The solenoid is a pulse-width modulated (PWM) actuator that regulates boost pressure by controlling vacuum or pressure to the wastegate actuator. If the ECU commands the solenoid ON and the feedback voltage remains below a specific threshold (typically indicating a short-to-ground or an open circuit), the P0249 code is stored. This prevents accurate boost regulation and may lead to overboost or underboost conditions.

Possible Causes

Short to ground in the wiring harness for solenoid B

Faulty wastegate solenoid (internal short/open)

High resistance or corrosion in the electrical connector

Faulty Engine Control Module (ECM/ECU) internal driver failure

Symptoms

Check Engine Light (MIL) illumination

Significant loss of engine power (Limp mode)

Unusual noises from the turbocharger area

Hesitation or surging during acceleration

Failed emissions test due to stored fault code

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P0249 - Turbocharger Wastegate Solenoid B Low

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P0249 - Turbocharger Wastegate Solenoid B Low

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