Operation - PCM Ground

Ground is provided through multiple pins of PCM connector. Depending on vehicle there may be as many as three different ground pins. There are power grounds and sensor grounds. The power grounds are used to control ground side of any relay, solenoid, ignition coil or injector. The signal ground is used for any input that uses sensor return for ground, and ground side of any internal processing component.

The SBEC III case is shielded to prevent RFI and EMI. The PCM case is grounded and must be firmly attached to a good, clean body ground. Internally all grounds are connected together, how ever there is noise suppression on sensor ground. For EMI and RFI protection case is also grounded separately from ground pins.