P0459 Subaru Code - EVAP System Purge Control Valve Circuit High
Quick Answer
The P0459 diagnostic trouble code (DTC) for Subaru vehicles indicates an issue with the EVAP (Evaporative Emission Control System) System Purge Control Valve Circuit. Common causes include Faulty Purge Control Valve: The purge control valve itself may be malfunctioning, causing the high voltage condition in the circuit, Wiring Issues: Damaged or corroded wiring in the circuit can lead to improper voltage levels being detected by the ECM, ECM Malfunction: A problem with the engine control module (ECM) can also trigger the P0459 code. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
- What it means
- P0459 Subaru indicates EVAP System Purge Control Valve Circuit High.
- Common causes
- Common causes include Faulty Purge Control Valve: The purge control valve itself may be malfunctioning, causing the high voltage condition in the circuit, Wiring Issues: Damaged or corroded wiring in the circuit can lead to improper voltage levels being detected by the ECM, ECM Malfunction: A problem with the engine control module (ECM) can also trigger the P0459 code.
- Severity
- Low - monitor the vehicle and repair when practical.
- Can I drive?
- The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P0459 Subaru Description
The P0459 diagnostic trouble code (DTC) for Subaru vehicles indicates an issue with the EVAP (Evaporative Emission Control System) System Purge Control Valve Circuit. This code specifically points to a high voltage condition detected in the circuit controlling the purge valve. The EVAP system is designed to capture and store fuel vapors from the fuel tank to prevent them from escaping into the atmosphere, helping to reduce emissions. The purge control valve is responsible for regulating the flow of fuel vapors from the charcoal canister to the engine intake manifold for combustion.
Common Causes of P0459 Subaru
- Faulty Purge Control Valve: The purge control valve itself may be malfunctioning, causing the high voltage condition in the circuit.
- Wiring Issues: Damaged or corroded wiring in the circuit can lead to improper voltage levels being detected by the ECM.
- ECM Malfunction: A problem with the engine control module (ECM) can also trigger the P0459 code.
- Charcoal Canister Issues: Problems with the charcoal canister or its connections can disrupt the operation of the EVAP system.
Symptoms of P0459 Subaru
- Check Engine Light: The most common symptom associated with the P0459 code is the illumination of the check engine light on the vehicle's dashboard.
- Rough Idle: A malfunctioning purge control valve can disrupt the engine's idle speed, causing it to run rough or stall.
- Poor Fuel Economy: A faulty EVAP system can lead to fuel vapors escaping, resulting in decreased fuel efficiency.
- Failed Emissions Test: Vehicles with unresolved EVAP system issues often fail emissions tests due to increased emissions.
How to Fix P0459 Subaru
- Diagnose the Issue: Use an OBD-II scanner to retrieve the specific code and conduct further testing to pinpoint the exact cause of the high voltage condition.
- Inspect Wiring: Check the wiring harness for any signs of damage, corrosion, or loose connections. Repair or replace as needed.
- Test Purge Control Valve: Test the purge control valve to determine if it is functioning properly. Replace if necessary.
- Check Charcoal Canister: Inspect the charcoal canister and its connections for any issues that may be affecting the EVAP system's operation.
- Clear Codes: Once the repairs have been made, clear the DTC and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0459 Subaru
The cost of repairing a P0459 code on a Subaru vehicle can vary depending on the specific cause of the issue. In general, the cost of parts for this repair can range from $100 to $300, with labor costs adding an additional $100 to $200. Overall, the total repair cost for addressing this code can be expected to fall within the range of $200 to $500. It's important to keep in mind that labor rates and part prices can vary based on the location of the repair shop, the make and model of the vehicle, and the type of engine. Be sure to obtain quotes from multiple repair facilities to ensure you are getting a fair price for the necessary repairs.
Tech Notes for P0459 Subaru
When is the Code Detected?
Need more information about the P0459 Subaru code?
Need more information on how to fix the P0459 Subaru code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0459 Subaru code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0459 Subaru Code
1. What does the OBDII code P0459 mean on a Subaru?
P0459 indicates that the EVAP (Evaporative Emission Control) System Purge Control Valve Circuit is experiencing a high voltage issue, which may affect the vehicle's ability to control fuel vapors.
2. What are the symptoms of a P0459 code on a Subaru?
Symptoms may include an illuminated check engine light, reduced fuel efficiency, difficulty starting the engine, or a faint fuel odor near the vehicle.
3. What causes a P0459 code on a Subaru?
Common causes include a faulty purge control valve, damaged or corroded wiring in the circuit, a malfunctioning ECM (Engine Control Module), or a short circuit.
4. How do you diagnose a P0459 code on a Subaru?
Diagnose the code by using an OBDII scanner, inspecting the purge control valve and its wiring for damage, testing for proper voltage and continuity, and checking for any related electrical issues.
5. Can I drive my Subaru with a P0459 code?
While the vehicle may still be driveable, ignoring the issue can lead to reduced performance, increased emissions, and possible damage to other components of the EVAP system.
6. How do you fix a P0459 code on a Subaru?
Repairs may include replacing the purge control valve, repairing or replacing damaged wiring, cleaning corroded electrical connections, or updating/reprogramming the ECM if needed.
7. How much does it cost to repair a P0459 code on a Subaru?
Repair costs can vary but typically range from $100 to $300, depending on whether the purge valve needs replacement or if there are wiring or ECM issues.
8. What tools are needed to fix a P0459 code on a Subaru?
You may need an OBDII scanner, a multimeter for voltage testing, basic hand tools, and potentially electrical contact cleaner for repairing corroded connections.
9. Can a loose or damaged gas cap cause a P0459 code on a Subaru?
No, a loose or damaged gas cap typically triggers a different EVAP-related code, such as P0456 or P0457, not P0459.
10. Is it common for a P0459 code to reappear after repairs?
If the underlying issue isn't fully addressed, such as undetected wiring damage or an intermittent ECM problem, the code may reappear. Always retest the system after completing repairs.
Discuss the causes and fixes for P0459 Subaru OBDII Code
-
2005 wrx p0459 evap purge valve circuit failed high. Yes it was the ecm, a tiny chip on the ecm. I soldered a new chip on my ecm I bought from ebay, Lutz automotive and it solved the issue. The chip is tiny, I'm not an electronics tech, my iron is nothing special. Part was 14 bucks. If you aren't comfortable installing the chip take it to a cb shop or someone who deals with electronics.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.