Purge valve with an internally shorted coil or faulty internal driver circuit; Wiring to the purge valve shorted to earth, chafed or damaged; Corroded, loose or damaged connector at the purge valve; Water or contamination in the valve connector or harness; Blown fuse or faulty relay supplying the valve, where fitted (depends on model); Faulty engine control unit output driver.

P0458

EVAP System Purge Control Valve A Circuit Low.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
58: FaultThe specific fault in that area

What it means

P0458 means the control unit has detected a low voltage or excessive current condition in the circuit for the evaporative emission purge control valve. The control unit drives the valve to let fuel vapour from the charcoal canister into the engine, and it saw the circuit voltage fall lower than expected. This is an electrical circuit fault, not a leak test failure, though the purge system will not work properly until it is fixed.

Symptoms

Engine warning light on
Difficulty restarting after refuelling
Slightly rough idle in some cases
Fuel smell near the engine bay or tank
Fuel economy may drop slightly
No noticeable symptoms in many cases

Possible causes

Purge valve with an internally shorted coil or faulty internal driver circuitlikely
Wiring to the purge valve shorted to earth, chafed or damagedlikely
Corroded, loose or damaged connector at the purge valvepossible
Water or contamination in the valve connector or harnesspossible
Blown fuse or faulty relay supplying the valve, where fitted (depends on model)possible
Faulty engine control unit output driverrare

How to diagnose

Read the stored codes and freeze frame data, noting engine temperature, load and whether other EVAP or fuelling codes are present
Visually inspect the purge valve, its connector and the wiring run for chafing, melted insulation, corrosion or water ingress
Check the relevant fuse and any relay for the purge valve circuit, using the wiring diagram for that model
Measure the purge valve coil resistance and compare it with the manufacturer specification for that engine
Back-probe the connector with the ignition on to check for the supply voltage, then check the control wire for a short to earth
Command the valve on and off with a bi-directional scan function and listen or feel for clicking, while checking the signal at the connector
Test the control wire for continuity back to the control unit and for a short to earth with the connector disconnected
If wiring and valve are good, check the control unit output and its power and earth supplies before considering the unit faulty

How to fix

Replace the purge control valve if the coil resistance is out of specification or it is internally shorted
Repair or replace damaged wiring that is shorted to earth, using proper soldered or crimped sealed repairs
Clean, repair or replace corroded or damaged connectors and terminals, and fix the source of water ingress
Replace a blown fuse only after finding the cause of the overload, and replace a faulty relay
Repair or replace the control unit only after all other causes are ruled out and its output is confirmed faulty

Can I keep driving?

Low severity

The car can normally be driven as the fault only affects the evaporative purge system, but get it checked soon so the warning light does not mask other faults and it can pass an emissions inspection. If the engine runs badly or you smell fuel strongly, have it inspected promptly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.