Fast Codes
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 1993 Mercury Tracer, 1993 Mercury Topaz, 1993 Mercury Sable, 1993 Mercury Grand Marquis, and 1993 Mercury Cougar. However, it is still accessible from the selected car via links, so may be relevant.
At start of KOEO SELF-TEST and after Wide Open Throttle (WOT) request in KOER SELF-TEST, PCM outputs short bursts of information, known as FAST CODES, which were used by manufacturer during assembly. With most equipment, these code bursts are not visible; an entire code sequence lasts less than 1/2 second. If this fluctuation is visible on test equipment, ignore it.