1990 Mercury Grand Marquis LSFACTORY OEM SERVICE PROCEDURE

Output State Check

The Output State Check is used as an aid in servicing output actuators associated with the EEC-IV system. It allows you to energize and de-energize most of the system output actuators on command. This mode is entered from the KOEO Self-Test after all codes have been received. At this time, leave self-test activated and depress throttle to initiate the test sequence. Each time throttle is depressed and released, the output actuators will change state (go from on to off, or off to on).

Factory Service Tools

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When to See a Mechanic

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

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

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