Self-Test Mode

1986 Mercury Sable LS, 4D SedanSECTION Self-Test Mode
  1. Enter self-test mode. Top part of display should show "000 or 00.0" (zeros). Press "FUEL ECON" button to check computer. Fuel computer portion of display should show software revision level and test number.
  2. Press "FUEL ECON" button to go through test 2 thru 11. A tone and a "P" or "NORMAL" on display indicates that tests have passed. On vehicles with new graphic software, test 5 does not exist (no display is shown).
  3. Press "FUEL ECON" button to go to test 12. Display test (test 12) shows 12 different test functions. Make sure that module displays illustrations shown. See Fuel Computer/System Scanner Module Self-Test Displays.
  4. Press "FUEL ECON" button to exit test. Self-test passes if display module goes off, comes on, then returns to a normal display.
Fig 1: Fuel Computer/System Scanner Module Self-Test Displays
G8220Courtesy of FORD MOTOR CO.
RENDER: 1.0x

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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.