P0498Generic code

P0498 Code: Evaporative Emission System Vent Control Circuit Low

The P0498 code indicates low voltage in the EVAP vent 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.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$30 to $250
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0498 code means

The vent valve lets clean air into the canister and closes during the leak test. It is open at rest, and the computer closes it when it needs to seal the system.

The computer monitors the control circuit from its own driver transistor. The P0498 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.

The valve usually sits next to the canister under the vehicle, exposed to dust and water. A valve that will not open makes the pump nozzle shut off while you fuel up, and one that will not close makes the leak test impossible.

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.

P0498 code symptoms

  • Check engine light on.
  • The pump nozzle shuts off while fueling.
  • EVAP monitor incomplete.

Likely causes of the P0498 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 P0498 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. Inspect the vent filter and clean off any dirt.
  7. Power it with 12 V. It should close with a click.

How to fix the P0498 code

  • Repair the connector, the wiring or the power supply.
  • Replace the EVAP vent 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; approximate resistance 20 to 30 ohms.
  • Approximate values only: check the manufacturer data for your engine.

Brand-specific notes

The vent valve normally sits next to the canister under the vehicle, so start with the connector and the wiring before you buy the part.

P0498 on GM

On GM vehicles the vent valve often gets clogged on vehicles that are driven on dirt roads.

P0498 on Toyota

On Toyota vehicles the vent valve often gets clogged on vehicles that are driven on dirt roads.

Frequently asked questions about P0498

Can I drive with a P0498 code?
Yes. A P0498 code normally does not affect driving. Repair it before your emissions inspection.
What does the EVAP vent valve do?
The vent valve lets clean air into the canister and closes during the leak test. It is open at rest, and the computer closes it when it needs to seal the system.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P0498?
Roughly $30 to $250, depending on whether it is wiring or the valve itself.
What does the P0498 code mean?
It is a generic OBD2 code that means the EVAP vent valve control circuit is reading low voltage, from a short to ground or a lack of power.
What is the most common cause of P0498?
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 P0498 code

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