P0458 EVAP purge valve: signal or voltage too low

By: Diagno editorial team · Updated: 2026-10-15

P0458 means: EVAP purge valve: signal or voltage too low. Fuel vapour from the tank is collected in a charcoal canister and burnt in the engine. OK to drive, but have it checked soon. The repair usually costs about €40–250 in Estonia. The most common cause: connector loose, damp or corroded.

What it means

Fuel vapour from the tank is collected in a charcoal canister and burnt in the engine. The computer found a leak or a valve fault in this system. It usually doesn't affect driving. The signal voltage is too low. Usually a wire is broken, a connector is loose or a wire is shorted to ground.

What you may notice

• Engine light on
• Sometimes a faint fuel smell
• The pump nozzle may click off early when filling

What could be wrong

1. 1Connector loose, damp or corroded
2. 2Wire broken or shorted to ground
3. 3Faulty valve
4. 4Engine computer fault (rare)

Repair difficulty: Easy

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? Tighten the fuel cap until it clicks. If you smell strong fuel, have it checked straight away. You can do the simpler checks yourself.

How we fix it

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the valve

Standard SAE description: Evaporative Emission System Purge Control Valve Circuit Low