Possible causes

– Faulty Evaporative Emission (EVAP) Purge Solenoid Control
– Evaporative Emission (EVAP) Purge Solenoid Control harness is open or shorted
– Evaporative Emission (EVAP) Purge Solenoid Control circuit poor electrical connection

When is the code detected?

The Powertrain Control Module (PCM) has detected a high voltage on the canister purge solenoid with the driver commanded on

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0459 PONTIAC Description

The Evaporative Emission System (EVAP) canister purge volume control solenoid valve uses a ON/OFF duty to control the flow rate of fuel vapor from the EVAP canister. The EVAP canister purge volume control solenoid valve is moved by ON/OFF pulses from the Powertrain Control Module (PCM). The longer the ON pulse, the greater the amount of fuel vapor that will flow through the valve.