Other wise known as JTEC??? Dont ask me why. The PCM is under the hood on 98.5 and up electronic controled Cummins motors. It is mounted to the firewall near the passenger hood hinge, As input signals to the PCM change the PCM adjustes its response to the output devices, The PCM controls

charging system
speed control
transmission
air conditioning
APPS
CPS
Auto shut down (ASD)
Battery temp
Battery voltage
Brake switch
CCD+
CCD-
CPS
Data link port for scan tool
fuel level
Alternator output
Ignition
Output shaft speed
Overdrive if auto
Cruze control
Tranny temp auto
Tranny pressure auto
ABS braking

SO next time you have the high pressure washer fired up stay away from the PCM or it will bite you