2006 Mazda 6 MazdaspeedFACTORY OEM SERVICE PROCEDURE

DTC P0091: Notes

DTC P0091 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0091 Fuel pressure regulator control circuit low
DETECTION CONDITION 
  • When the PCM turns the spill valve control solenoid valve off but the spill valve control solenoid valve control circuit voltage is low, the PCM determines that the spill valve control solenoid valve control circuit has malfunction.

    MONITORING CONDITIONS 

    • The following conditions are met:
      • Engine speed is 3, 00 RPM or less. 
      • Battery voltage is 10 V or more. 

Diagnostic support note 
  • This is a continuous monitor (CCM).
  • The MIL illuminates if the PCM detects the above malfunction condition during first drive cycle.
  • FREEZE FRAME DATA is available.
  • DTCs are stored in the PCM memory.
POSSIBLE CAUSE 
  • Spill valve control solenoid valve malfunction
  • Open circuit in the wiring harness between high pressure fuel pump terminal A and PCM terminal 1A
  • Open circuit in the wiring harness between high pressure fuel pump terminal B and PCM terminal 1B
  • Short to ground in the wiring harness between high pressure fuel pump terminal A and PCM terminal 1A
  • Short to ground in the wiring harness between high pressure fuel pump terminal B and PCM terminal 1B
  • Connector or terminal malfunction
  • PCM malfunction
G04324087Courtesy of MAZDA MOTORS CORP.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.