Skip to content
Book on WhatsApp

P04B8

Fuel Fill Door Position Sensor Circuit

A general circuit fault is detected on the fuel fill door position sensor or switch - the ECU cannot determine whether the door is open or closed. Usually an open in supply, signal or ground.

  • Check engine light: Not always
  • Emissions related: No
  • Repair difficulty: easy

Common causes

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

  • Open in sensor circuitCommon

Parts involved

  • Fuel Fill Door Position Sensor

P04B8 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.