OBD-II trouble code
P0458: Evaporative Emission System Purge Control Valve Circuit Low
SAE J2012 names a low purge-valve control circuit, meaning the voltage, frequency, or other signal at the controller pin is below the manufacturer's range. The 2006 Ford PCED hunts the matching short to ground 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 P0458 mean?
P0458 is Evaporative Emission System Purge Control Valve Circuit Low in SAE J2012 APR2002. Section 3 of that standard says low input is the voltage, frequency, or other characteristic measured at the control-module pin that is below the normal operating range. The specific level is set by the manufacturer. Low is not a synonym for a vacuum leak, and it is not the open-circuit code. Open is P0444. High is P0459. The generic circuit code is P0443.
The 2006 Ford PCED pinpoint HX does not list P0458. It tests the purge output under P0443. After the commanded test lamp between EVAPCP and VPWR, the short-to-ground check is HX7: with the diagnostic-tool connector disconnected, resistance from the PCM EVAPCP pin to ground must be greater than 10,000 ohms. If it is not, the pinpoint says to repair the short circuit. The winding, measured key off on the component, is 2.5–7 ohms for the common purge valve and 30–50 ohms for the Ford GT diaphragm valve. A winding near zero ohms is outside both bands and is the solenoid, not the harness short HX7 is measuring.
Volkswagen bulletin 20 17 02 lists P0458 for 2009–2017 Volkswagen gasoline vehicles except Routan. The published steps are a smoke test, an N80 click test, and a vacuum seal check. They do not measure a low-circuit threshold in volts. No click means the bulletin does not apply and guided fault finding continues, which is where a short to ground has to be separated from an open winding.
Common causes
- EVAPCP shorted to ground on the 2006 Ford PCED: HX7 fails when resistance from the PCM pin to ground is not greater than 10,000 ohms
- A purge winding below both Ford bands, 2.5 ohms on the common valve and 30 ohms on the Ford GT diaphragm valve, measured key off with the connector unplugged
- A connector fault found while the valve is unplugged for that ohms check
- On the Volkswagen bulletin, a P0458 that remains after N80 has clicked and held vacuum, which returns the car to guided fault finding
- A supply-side open, which Ford HX5 identifies when VPWR is not greater than 10 volts, is a different step from the short-to-ground check
Symptoms
- Malfunction indicator lamp with P0458
- On the Ford pinpoint, a control wire that is not above 10,000 ohms to ground
- A purge valve that measures near 0 ohms across its own pins, which fails the 2.5–7 ohm and the 30–50 ohm Ford checks
- No click from N80 when the Volkswagen output test is run
- The Ford HX7 result is a wiring repair, not a described change in idle quality
Diagnostic steps
- 1.Use the chart that names P0458. If the only purge-circuit code in the book is P0443, you are not in a P0458 procedure. The 2006 Ford PCED is that second case.
- 2.Key off. Unplug the purge valve and measure the winding on the component, not back through the harness. The 2006 Ford common valve passes at 2.5–7 ohms. The Ford GT diaphragm valve passes at 30–50 ohms. A near-zero reading replaces the valve on that pinpoint. An infinite reading is the open-circuit case, P0444 on the SAE list, and HX6 on the Ford list.
- 3.With the diagnostic connector disconnected, measure the PCM end of the control wire to ground. Greater than 10,000 ohms continues the Ford pinpoint. Less than that is the short HX7 says to repair. Do not do this ohms check with the circuit powered.
- 4.On 2009–2017 Volkswagen gasoline vehicles except Routan, smoke-test and command N80 before replacing it. A click plus a passing vacuum check, at about −0.6 bar on the removable-hose engines or 0 psi or higher on the running-engine gauge engines listed in bulletin 20 17 02, means the valve is not the cause. Guided fault finding then has to find the low circuit.
- 5.Do not apply 12 volts to a control pin to force the valve while it is still plugged into the harness. The Ford check uses a non-powered test lamp between EVAPCP and VPWR and commands the output. A powered jumper into the module driver is not that test.
- 6.Repair the short or replace the winding the chart failed, clear the codes the test itself set, and rerun the evaporative monitor that procedure names.
Repair cost
$200 – $400
The priced repair is the purge valve, about $180 to $370 installed. The band rounds that total to $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.