P04C9
Fuel Fill Door Open Request Performance Stuck Off
The open-request switch never registers an active state - either the contact stays open mechanically or the wiring is permanently broken. The driver cannot trigger door release.
- Check engine light: Not always
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Switch contact stuck openCommon
- Carbon or debris buildup preventing free movementLess likely
- Component wear with age - mechanical playLess likely
Parts involved
- Fuel Fill Door Request Switch
P04C9 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.