| DTC Data Sheet | |
| System | Powertrain |
| Standard | SAE J2012 / ISO 15031-6 |
| Fault type | Circuit Low |
| Official meaning | Evaporative Emission System Purge Control Valve Circuit Low |
The PCM has detected a low-side fault on the EVAP purge control valve circuit — the signal is sitting below the expected voltage range, indicating a short to ground or open ground on the valve coil.
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P0458 Quick Answer
The PCM has detected a low-side fault on the EVAP purge control valve circuit — the signal is sitting below the expected voltage range, indicating a short to ground or open ground on the valve coil. The first thing to check is engine oil level, condition, and viscosity — many P045-range faults are oil-driven before they are electrical.
What Does P0458 Mean?
Evaporative Emission System Purge Control Valve Circuit Low. The PCM has detected a low-side fault on the EVAP purge control valve circuit — the signal is sitting below the expected voltage range, indicating a short to ground or open ground on the valve coil.
Symptoms
- Check engine light
- Rarely any drivability symptoms
- EVAP monitor will not run to completion (fails emissions readiness)
- Possible fuel-cap-loose smell if purge valve is stuck open
Common Causes
- Failed EVAP purge solenoid (internal short)
- Wiring shorted to ground in the purge valve harness
- Open ground or chassis-ground corrosion at the purge valve circuit
- Damaged connector or backed-out terminal at the purge valve
- PCM driver failure (rare)
Diagnosis Steps
You’ll need a scan tool capable of reading live powertrain data, a digital multimeter, and access to the wiring diagram for the specific platform.
- Locate the purge valve — usually mounted near the intake manifold or on the engine compartment side of the firewall.
- Disconnect the connector and measure resistance across the valve terminals (typical 22–30 ohms for most platforms).
- Resistance lower than spec confirms an internally shorted solenoid.
- With the valve disconnected, key on, back-probe the harness — should see 12 V on the supply pin.
- On the control pin, the PCM normally pulses ground; an unbroken short to ground here flags P0458.
- Wiggle-test the harness to expose chafing damage where the wire passes through pinch points.
Possible Fixes
- Replace the EVAP purge valve solenoid
- Repair shorted or chafed wiring in the purge circuit
- Connector repair when terminals are damaged or oil-contaminated
Can I Still Drive With P0458?
The vehicle will usually still drive with P0458 stored, but performance and fuel economy are degraded. The fault disables or limits the affected actuator, and the PCM may inhibit emissions monitors. Drive to a workshop, but don’t ignore the code long-term — VVT and EVAP failures often cascade into related faults if left untreated.
How Serious Is This Code?
P0458 is a moderate-priority fault. It will not prevent the engine from running but will affect drivability, emissions, and over time can damage related components (cam phaser wear, catalytic converter on EVAP-related codes). Address within a few drive cycles.
FAQ
Will P0458 clear itself?
Only if the underlying fault was intermittent and self-corrected. Most P0458 root causes (failed solenoid, wiring damage, blocked screen) are persistent and require physical repair.
Can I clear P0458 without fixing it?
You can clear it with a scan tool, but it will return as soon as the fault condition reappears — typically within one or two drive cycles.
Is P0458 related to other codes?
Often, yes. Cam-position and EVAP faults frequently set adjacent codes — if P0458 is present, scan for related codes in the same range and address them as a group rather than one at a time.