P0498 — EVAP System Vent Valve Control Circuit Low

P0498: EVAP System Vent Valve Control Circuit Low — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

EVAP System Vent Valve Control Circuit Low. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • The malfunction indicator may illuminate; the fault does not necessarily produce an obvious driving symptom.
  • A warning lamp may appear without a noticeable driving symptom.

Possible causes

  • Open, damaged or corroded vent-valve wiring and poor connectors may cause a low control-circuit indication.
  • A failed vent-valve coil, fuse or its power feed may affect circuit operation.
  • A wiring or connector defect should be excluded before a costly component replacement.

What to check

  • Read P0498 and related faults; retain freeze-frame information.
  • Inspect the EVAP vent valve plug, harness and applicable fuse before interpreting tank sealing.
  • Check control and supply circuits with the OEM wiring diagram; a low electrical indication is not a direct measurement of vapor flow.
  • Correct only the confirmed defect, then verify the result under the maker's specified conditions.

Also written as: P0498-00, P049800, PO498 (some scan tools add the fault-type byte, e.g. -00).