Fault code P0459 – evaporative emission system purge control valve circuit high

Fault code P0459 is called “Evaporative Emission (EVAP) System Purge Control Valve Circuit High” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P0459

This diagnostic trouble code (DTC) is a generic code. Error P0459 is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

Fault code P0459 – evaporative emission system purge control valve circuit high

This code indicates that part of the EVAP control system is no longer functioning properly. The EVAP system consists of many parts, including (but not limited to) the tank cap, fuel lines, carbon tank, purge valve, and others.

The emission control system (EVAP) prevents fuel vapor from escaping from the vehicle’s fuel system. Fuel vapors are routed through hoses to a carbon canister for storage. Later, when the engine is running, the purge control valve opens, allowing fuel vapors to be drawn in under vacuum.

The EVAP canister purge is controlled by a valve that allows fuel vapors to be drawn in due to the vacuum created by engine operation. They flow from the fuel tank into the engine for combustion, rather than escaping into the atmosphere.

The purge valve measures the desired amount of fuel vapor. Controlled by the vehicle’s Powertrain Control Module (PCM) or Engine Control Module (ECM). If the PCM/ECM controller does not see the expected voltages in the circuit when the purge valve is commanded, fault code P0459 is set.

Symptoms of vehicle malfunctions

The main signal that an error P0459 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. The “Check engine” control lamp on the control panel will light up (the code will be written in the ECM memory as a fault).
  2. Possible lean mixture or rough engine operation if the purge valve is stuck in the open position.
  3. Excessive pressure in the gas tank in the form of a “whistling” sound when removing the cap, this indicates that the purge valve does not work at all or is stuck in the closed position.
  4. A slight increase in fuel consumption.

The severity of fault code P0459 is medium. The car will be able to continue driving, but the harmful emissions will increase. Which, in practice, will not allow passing the toxicity test.

Factors that can cause this error code

The error code P0459 can mean that one or more of the following problems have occurred:

  • Internal short circuit or breakage of purge valve.
  • Breakage in wiring harness.
  • Shorted or frayed connector.
  • Corrosion or resistance in connector.
  • Open or shorted circuit to purge solenoid valve.
  • Driver circuit inside the transmission control module (PCM) is faulty.

How to fix or reset OBD-2 code P0459

Some suggested steps for troubleshooting and fix the error code P0459:

  1. Repair damaged EVAP lines.
  2. Repair open or shorted purge solenoid voltage supply circuit.
  3. Repair circuit going to PCM.
  4. Replace the purge solenoid valve.
  5. Repair or repair the restriction in the EVAP line.
  6. Repair or clean the connector.
  7. Replace PCM.

Diagnose and repair of problems

Starting the diagnosis of P0459, use the diagnostic tool to activate the purge valve. Listen for a clicking sound from the purge solenoid. It should click once, and on some models it may click again.

If it does not click when you activate the diagnostic tool, disconnect the connector and check the solenoid and connector for damage. Then check the battery voltage on the lead wire with the key turned on.

If there is voltage, ground the contact manually with a jumper and see if the valve clicks. If it does, the solenoid is working properly, but there is a problem with the control circuit. When, when manually grounding it does not click, replace the purge solenoid.

To check for a control circuit problem, reconnect the solenoid and disconnect the ground wire from the connector. With the ground wire disconnected from the controller, turn on the key and manually ground the purge valve control wire.

The solenoid should click, so there is no problem with the control wire to the solenoid, and there is a problem with the purge valve actuator circuit from the ECM. If it does not click, then there is a break in the wiring between the ECM and the solenoid.

When fixing the P0459 fault, you must clearly understand what you are doing. Otherwise, get help from a specialist.

On which vehicles does this problem occur most frequently

Fault code P0459 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • BMW
  • Chevrolet (Spark, Traverse)
  • Ford (Focus)
  • Hyundai
  • Kia
  • Renault (Duster)
  • Subaru
  • Volkswagen
  • Volvo
  • LADA (Granta, Priora)

Fault code P0459 can sometimes be found with other errors. The most common are the following: P0443, P0444, P0445, P0458.

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