Fast Codes
WARNING: This page is about a different car, the 1993 Ford Mustang. 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.