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Fast Codes

WARNING: This page is about a different car, the 1995 Lincoln Mark VIII. 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. These codes contain the identical information as slow codes, but are transmitted at 100 times the normal rate. With most equipment (except Super Star II tester), these code bursts are not visible. An entire code sequence lasts for less than1/2 second.

Fig 1: Reading Diagnostic Trouble Codes Using MIL/CHECK ENGINE Light (Using Analog Voltmeter Is Similar)
G95F12919Courtesy of FORD MOTOR CO.
Fig 2: Reading Diagnostic Trouble Codes
G95I12920Courtesy of FORD MOTOR CO.