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P28C3

EVAP System High Load Purge Line B Performance

The ECM detects insufficient flow or pressure in the high-load purge line B of the evaporative emissions system. Purge cannot be commanded effectively under high engine load.

  • Check engine light: Yes
  • Emissions related: Yes
  • Repair difficulty: medium

Symptoms

  • Check engine light on
  • Possible smell of fuel near tank or engine bay
  • Failed emissions inspection
  • Loose-cap warning may appear

Common causes

Ordered by how often each turns out to be the cause.

  • Purge line B restricted or kinkedCommon
  • Purge valve B partially openPossible

Parts involved

  • EVAP Purge Valve B
  • EVAP Purge Line B
  • Intake Manifold

P28C3 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.