P0459 OBD-II Trouble Code: Evaporative Emissions System Purge Control Valve Circuit High

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0459 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0459 code

P0459 is a diagnostic trouble code (DTC) for "Evaporative Emissions System Purge Control Valve Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0459 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0459 code definition

The P0459 code means that there has been a problem experienced with the vehicle’s evaporative (EVAP) system.

What the P0459 code means

If the P0459 code is set in the car’s computer, it means there has been a problem experienced within the evaporative system. This system includes a wide range of components, including the gas cap, the fuel filter, the system pressure sensor, flow sensor and many more. The car’s computer monitors fuel system pressure through a voltage reading. When that voltage is higher than expected, the system may turn on the Check Engine light.

What causes the P0459 code?

Potential causes for the P0459 code are varied, but they include the following:

  • Loose gas cap
  • Failed or damaged gasket on the gas cap
  • Damaged charcoal canister
  • Failed purge control solenoid
  • Damaged vacuum hoses
  • Damaged fuel vapor hoses
  • Faulty pressure sensor
  • Faulty flow sensor
  • Faulty PCM (rare)

What are the symptoms of the P0459 code?

The only symptom of a P0459 code is the Check Engine light turning on in the dash. This code should not result in drivability problems.

How does a mechanic diagnose the P0459 code?

The first step to diagnosing the P0459 code is connecting an OBD II scanner to the car’s computer and reading the codes stored there. It is likely there are several other evaporative system codes present. Next, the car should be test driven to see if the codes reset.

Following the test drive, the mechanic should begin with a visual and physical examination of the gas cap’s condition, including whether it is correctly installed and the condition of the gasket. If the problem is not related to the gas cap, the mechanic should inspect all vacuum lines for cracking or damage. The purge control solenoid should be tested (note that this may require the use of a vehicle lift and a smoke machine). A mechanic may also need to inspect all other evaporative system components, including the charcoal canister, fuel vapor hoses, pressure sensor, flow sensor and more. Note that solenoids should be removed from the vehicle before being tested.

Common mistakes when diagnosing the P0459 code

One of the most common mistakes seen when diagnosing the P0459 code is replacing parts without first performing a full diagnostic on the vacuum system. Loss of vacuum is the primary cause for the P0459 code to be set in the computer, and should be ruled out before any parts are replaced.

How serious is the P0459 code?

While the P0459 code will not result in drivability problems with your vehicle, it can lead to combustible fuel vapors being released into the atmosphere. This will also result in the car not being able to pass emissions testing. In a worst-case scenario, it can also have an adverse effect on fuel economy as the engine may not be able to burn fuel vapor correctly.

What repairs can fix the P0459 code?

The most common repair for the P0459 code is to inspect the fuel cap and reinstall it. Gas cap replacement is also common. However, in older vehicles, as well as those driven in areas where adverse conditions are common, vacuum line deterioration can be common. Other repairs include replacing damaged or failed solenoids, replacing the charcoal canister or a faulty sensor.

Additional comments for consideration regarding the P0459 code

While an incorrectly installed gas cap is one of the primary causes of the P0459 code, the vehicle should be thoroughly inspected to rule out any other potential causes, such as damaged vacuum or fuel vapor lines.

Need help with a P0459 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
Check Engine Light
P0459

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0459 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,526

Rating Summary
3,215
155
41
23
92
3,215
155
41
23
92

Ben

38 years of experience
883 reviews
Ben
38 years of experience
Quick, knowledgeable and friendly service. Will definitely book again.
2009 VOLKSWAGEN TIGUAN - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

Robert

28 years of experience
500 reviews
Robert
28 years of experience
good
2005 DODGE GRAND CARAVAN - CHECK ENGINE LIGHT IS ON - SAN JOSE, CALIFORNIA

Joe

40 years of experience
576 reviews
Joe
40 years of experience
Great guy knows his stuff..Very professional...Timely work
2002 CHEVROLET MONTE CARLO - CHECK ENGINE LIGHT IS ON - CLEARWATER, FLORIDA

William

31 years of experience
144 reviews
William
31 years of experience
Highly recommend!! Honest & straight forward!!! I will use in future!!! (when needed)
2002 CHRYSLER SEBRING - CHECK ENGINE LIGHT IS ON - PEORIA, ARIZONA

More related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...

Related questions

Q: How to diagnose coded p0352,0352,0353, already had new plugs and coils before code throw

Hello. The codes listed are for problems with the electrical circuits of ignition coils A, B, and C. If the coils have been replaced it may be possible that the wiring to them is the source of the issue. You...

Q: Check Engine Light is on - code P0350

Hi there. Changing the plugs and coils is definitely a plausible route to take; however, this sounds like you have an open circuit in the wire harness, anywhere from the coils to the ECM. Using a digital volt/ohm meter...

Q: P0420 - CATALYST B1 DETERIORATION

Hello - it is possible the 2 problems are related, but likely only over a long period of time. The P0420 code is a "low efficiency catalytic converter" for Bank2 - which include cylinder 1. And yes, that warning is...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com