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U066F

Lost Communication With Low Pressure Fuel System Sensor

The vehicle bus reports loss of communication with smart low-pressure fuel system sensor. Lift-pump pressure feedback is unavailable; high-pressure pump and injection switch to a fail-safe map.

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

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Common causes

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

  • Bus wiring open or shortedCommon
  • Module without power or groundPossible
  • Module failedPossible

Parts involved

  • Low Pressure Fuel Sensor
  • Vehicle Bus Wiring

U066F 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.