Power and Ground Distribution: Description and Operation

Circuit Z12 connects to cavities 2 and 22 of the Powertrain control Module
(PCM). The Z12 circuit provides ground for PCM internal drivers that operate high current devices like the injectors and ignition coils.

Internal to the PCM, the power (device) ground circuit connects to the PCM sensor return circuit (from circuit K4) and the signal ground circuit (Z11).