P0458Generic code

P0458 Code: Evaporative Emission System Purge Control Valve Circuit Low

The P0458 code indicates low voltage in the EVAP purge valve control circuit, from a short to ground or a lack of power. Check the fuse, relay, connector and wiring before replacing the valve. The code usually does not affect driving much.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$30 to $200
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0458 code means

The purge valve opens the path for the vapors stored in the canister to flow into the intake, where they are burned. The computer opens and closes it with a pulsed signal.

The computer monitors the control circuit from its own driver transistor. The P0458 code indicates low voltage in the control circuit (a short to ground or a lack of power). Before replacing the component, check the fuse, relay, connector and wiring, since they are the most common cause.

A valve that will not open keeps the canister from emptying (EVAP monitor incomplete). One that sticks open lets vapors and air into the engine all the time, causing hard starting after fueling and an unstable idle.

To confirm it, unplug the component with the key on and watch what happens to the reading or the code. If the value jumps to the opposite extreme, the wiring is fine and the component is the one pulling the signal to ground. If it does not change, look for the short in the wire, starting where the harness rubs against the engine, the chassis or the exhaust.

P0458 code symptoms

  • Check engine light on.
  • Hard starting after fueling.
  • Unstable idle.
  • Gasoline smell.

Likely causes of the P0458 code

  1. Control wire shorted to ground. The component may stay energized all the time, or the computer cuts the command to protect itself.
  2. Interrupted power supply, from a fuse or relay.
  3. Shorted component, with a resistance far lower than specified.

How to diagnose the P0458 code step by step

  1. Command the component with the scan tool and check whether it responds.
  2. Check the fuse and relay.
  3. Measure the supply at the connector: battery voltage with the key on or when it is commanded.
  4. Measure the component resistance and compare it with the manual. Also check the insulation to ground.
  5. Check the control wire for continuity and for shorts.
  6. With the engine off, blow through the valve. No air should pass.
  7. Power it with 12 V or with the scan tool. It should open with a click.

How to fix the P0458 code

  • Repair the connector, the wiring or the power supply.
  • Replace the EVAP purge valve if it does not respond with correct power and control.
  • Clear the codes and verify that the monitor completes.

Technical reference data

  • 12 V solenoid with PWM control; approximate resistance 20 to 30 ohms.
  • Approximate values only: check the manufacturer data for your engine.

Brand-specific notes

This fault is very common on several manufacturers, and the purge valve is an inexpensive part.

P0458 on GM

Very common on GM vehicles, and the part is cheap.

P0458 on Ford

Very common on Ford vehicles, and the part is cheap.

P0458 on Toyota

Very common on Toyota vehicles, and the part is cheap.

P0458 on Hyundai

Very common on Hyundai vehicles, and the part is cheap.

Frequently asked questions about P0458

Can I drive with a P0458 code?
Yes. A P0458 code normally does not affect driving. Repair it before your emissions inspection.
What does the EVAP purge valve do?
The purge valve opens the path for the vapors stored in the canister to flow into the intake so they get burned. The computer opens and closes it with a pulsed signal.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P0458?
Roughly $30 to $200, depending on whether it is wiring or the valve itself.
What does the P0458 code mean?
It is a generic OBD2 code that means the EVAP purge valve control circuit is reading low voltage, from a short to ground or a lack of power.
What is the most common cause of P0458?
A control wire shorted to ground, an interrupted power supply from a fuse or relay, or a shorted valve. Check the wiring and fuse before buying the valve.

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Questions about the P0458 code

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