Vehicle applicability: This diagnostic supplement covers multiple Ford vehicles and engines. Follow the application named in the source below. Some references apply to vehicles other than Mustang.
Description and Operation 1-81
Ignition Systems
Engine Crank/Engine Running
During engine crank the PCM fires 2 spark plugs simultaneously. Of the 2 spark plugs fired, one is under compression while the other is on the exhaust stroke. Both spark plugs fire until camshaft position is identified by a successful CMP sensor signal. Once camshaft position is identified only the cylinder under compression is fired.
Camshaft Position Failure Mode Effects Management (FMEM)
During camshaft position FMEM the COP ignition works the same as during engine crank. This allows the engine to operate without the PCM knowing if cylinder 1 is under compression or exhaust.
2016 Powertrain Control/Emissions Diagnosis, Gasoline Engines, 3/2015
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.