What causes fault code P0459?

• Most likely: Short to voltage (12V) in the purge valve wiring harness • Likely: Defective EVAP purge control solenoid (internal short) • Possible: Corroded or damaged pins in the electrical connector • Rare: Internal failure in the Engine Control Module (PCM/ECU)

How do you fix fault code P0459?

STEP 1: Visually inspect the purge valve connector for corrosion or moisture. Inspect the wiring harness for signs of chafing or heat damage. STEP 2: Measure the resistance (Ohms) of the purge valve solenoid. A normal reading is typically 15-40 Ohms. A reading near 0 Ohms indicates an internal short. STEP 3: Check voltage at the connector with the ignition on. If constant 12V is present on the control side when the solenoid should be inactive, there's a short to voltage in the wiring. STEP 4: Use a bidirectional scan tool to command the purge valve ON/OFF (Duty Cycle test) and verify function. Replace component if it fails to operate correctly.

Powertrain (Engine & Gearbox)Standard EOBD

P0459 - Evaporative Emission System Purge Control Valve Circuit High

Q: What are the symptoms of fault code P0459?

• Check engine light (MIL) illuminated • Strong odor of fuel around the vehicle • Rough idle, particularly after refueling • Reduced fuel economy • Failed emissions test

Last updated:1 February 2026

Related:EVAP Purge Valve / Tankurluftningsventil, Charcoal Canister / Kolkanister, ECU / PCM, Wiring Harness

System

Powertrain (Engine & Gearbox)

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Technical Description

The P0459 code indicates that the Engine Control Module (ECM/PCM) has detected a voltage signal in the Evaporative Emission (EVAP) system purge control valve circuit that is higher than the manufacturer's specified range. This solenoid valve is responsible for allowing fuel vapors stored in the charcoal canister to be drawn into the engine to be burned. A 'High' circuit code typically signifies a short to voltage in the wiring harness or an internal short within the solenoid coil itself, causing the control circuit to stay at a high voltage level.

Possible Causes

Short to voltage (12V) in the purge valve wiring harness

Defective EVAP purge control solenoid (internal short)

Corroded or damaged pins in the electrical connector

Internal failure in the Engine Control Module (PCM/ECU)

Symptoms

Check engine light (MIL) illuminated

Strong odor of fuel around the vehicle

Rough idle, particularly after refueling

Reduced fuel economy

Failed emissions test

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P0459 - Evaporative Emission System Purge Control Valve Circuit High

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P0459 - Evaporative Emission System Purge Control Valve Circuit High

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