OBD-II trouble code
P0459: Evaporative Emission System Purge Control Valve Circuit High
SAE J2012 names a high purge-valve control circuit, measured at the controller pin. On the 2006 Ford PCED the supply at the purge valve must be greater than 10 volts, and that test is filed under P0443.
Quick facts
- System
- Powertrain
- Category
- EVAP System
- Severity
- Low severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $200 – $400
- DIY difficulty
- Intermediate DIY
Browse every code in P0400–P0499, or start from the full code library.
What does P0459 mean?
P0459 is Evaporative Emission System Purge Control Valve Circuit High in SAE J2012 APR2002. High means the characteristic measured at the module pin is above the range that manufacturer set. It is the opposite end from P0458 and a different description from the open code P0444. A low-side driver can see a high voltage for more than one reason, including an open load and a control wire shorted to power. The standard does not pick which of those a given car uses. The schematic does.
The 2006 Ford PCED does not list P0459. Under P0443, HX5 measures VPWR at the purge-valve harness, pin 1, to battery negative, key on and engine off. The voltage must be greater than 10 volts. If it is not, the pinpoint says to repair the open circuit. That is a missing supply, which is not the same finding as a control wire shorted to power. The commanded test is a non-powered test lamp between EVAPCP and VPWR. The winding is 2.5–7 ohms, or 30–50 ohms on the Ford GT diaphragm valve. An open winding is an infinite reading on that unplugged valve and is repaired by installing a valve, which the pinpoint states at HX3 and HX4.
Volkswagen bulletin 20 17 02 lists P0459 on 2009–2017 Volkswagen gasoline vehicles except Routan. The steps are the smoke test, the N80 click, and the engine-code vacuum check. A valve that clicks is called operational, and the vacuum check then decides whether it seals. No click leaves the bulletin and returns the car to guided fault finding, where an open winding, an open wire, and a short to power are separated with that vehicle's diagram.
GM's 2008 GRP09 sheet stores a purge-solenoid driver mismatch as P0443, Type B, 20 failures out of 25 samples, with ignition between 11 and 18 volts. It does not publish a separate P0459 threshold.
Common causes
- VPWR at the purge-valve connector not greater than 10 volts on the 2006 Ford PCED, which HX5 repairs as an open supply
- An unplugged or open winding on that Ford pinpoint: outside 2.5–7 ohms, or outside 30–50 ohms on the Ford GT diaphragm valve
- A control-circuit short to power, only when the diagram and the pinpoint you are in tell you to measure the control wire for voltage rather than the supply pin
- On the Volkswagen bulletin, N80 that does not click, which is guided fault finding rather than a valve that failed the vacuum hold
- On 2008 GRP09 vehicles, a purge driver whose commanded state does not match the circuit, stored as P0443 rather than as P0459
Symptoms
- Malfunction indicator lamp with P0459
- On the Ford supply check, less than or equal to 10 volts on VPWR at the valve with the key on and the engine off
- No click from N80 during the Volkswagen output test
- A purge valve that will not meet the ohm band for the valve on the bench, key off
- The Ford lamp test does not list a fuel smell or a stall as the electrical result
Diagnostic steps
- 1.Separate the supply from the control wire on the diagram before any voltage is called high. On the 2006 Ford PCED, VPWR pin 1 to battery negative must be greater than 10 volts, key on, engine off. That failure is an open supply, repaired as such.
- 2.Key off, unplug the valve, and measure the component. Pass is 2.5–7 ohms on the common Ford purge valve and 30–50 ohms on the Ford GT diaphragm valve. Infinite is a valve replacement on that pinpoint. Do not measure the harness side and call an open wire a failed winding.
- 3.Command the output with a non-powered test lamp between EVAPCP and VPWR. The lamp must follow the command. A short to power on the control wire is the next Ford circuit check only if the lamp result and the pinpoint send you there. Do not declare every P0459 a short to battery.
- 4.On 2009–2017 Volkswagen gasoline vehicles except Routan, bulletin 20 17 02: smoke-test, command N80, and do not replace it if it clicks and holds vacuum. Removable-hose engines use about −0.6 bar on the flow-indicator side. CCTA, CBFA, CGFA, CNLA, and CZTA use the running-engine gauge, which should read 0 psi or higher with the connector unplugged. Vacuum on that gauge replaces N80. No click continues guided fault finding.
- 5.On a 2008 GRP09 truck or utility, a purge electrical fault is P0443 on that sheet. Do not import a P0459 voltage from a different calibration.
- 6.Clear codes set by unplugging the valve, and verify with the monitor the procedure names. The Volkswagen bulletin warns that a road test may not run the tank-leakage diagnostic.
Repair cost
$200 – $400
A purge valve on this circuit is about $180 to $370 in parts and labor. Rounded, the usual total is $200 to $400.
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Related repairs
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.