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P2668

Fuel Mode Indicator Lamp Control Circuit

The fuel mode indicator lamp circuit (showing whether a bi-fuel vehicle currently runs on gasoline or alternative fuel) is faulty. Driver may not know the active fuel.

  • Check engine light: Yes
  • Emissions related: No
  • Repair difficulty: easy

Common causes

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

  • Burnt-out indicator bulbCommon
  • Open or shorted wire to the clusterPossible

Parts involved

  • Fuel Mode Lamp
  • Instrument Cluster
  • Wiring Harness

P2668 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.