87G - 7
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87G
V6 MR-372-J84-87G000$132_eng.mif
UPC
Vdiag No.: 44ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation
1. GENERAL FUNCTIONING
The UPC particpates in the following functions:
–distributing and protecting the electrical power,
–keyless vehicles,
–wipers,
–lighting,
–de-icing,
–air conditioning,
–oil pressure detection.
Distributing and protecting electrical power
The main function of the UPC is to switch on and distribute part of the power in order to supply the vehicle systems,
actuators or computers.
Another part of the power supply distribution is housed in the Engine Interconnection Unit but is not controlled
electronically by the computer.
+12 V battery feed
The UPC receives energy from the battery via the 1 track screwed connector and redistributes +12 V around the
vehicle.
+ after ignition feed
The UCH requests the + APC via the multiplex network. When the UPC receives this request, it controls the APC
relay unconditionally.
Energy management
The computer transmits the signal to load the alternator on the multiplex network.
Keyless vehicle
In the Keyless vehicle function, the UPC participates in the start-up sub-function. The computer:
–receives the request to start up the UCH via the multiplex network,
–check that the start-up conditions have been met then controls the starter relay,
–can inhibit or turn off the starter relay command by means of a forbid start-up signal transmitted by the
injection computer on the multiplex network.
Air conditioning
For the operation of this function and the role of the UPC in setting up this function (see 62A, Air conditioning,
Function architecture and General functioning mode).
Cold loop
The computer receives the compressor switch-on request from the injection via the multiplex network.
The computer controls the compressor clutch activation relay.
Heating
The computer also controls the de-icing of the rear tailgate window and the electric rear view mirrors.
Fan assembly
When prompted for the engine check request, the UPC supplies the GMV with power.
MR-372-J84-87G000$132_eng.mif
