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
87G - 56
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Fault Finding Chart (ALP)
87G
V6 MR-372-J84-87G000$924_eng.mif
UPC
Vdiag No.: 44
ALP 3 Various passenger compartment functions do not light up
NOTESThe side lights must not be faulty, if they are, refer to the interpretation of command
AC003 Side lights.
Check the condition and connection of the faulty function(s).
Repair if necessary.
Check for the presence of earth on the defective function(s).
Repair if necessary.
With the side lights on, check for the presence of a +12 V supply on the defective function or functions.
If it is in order, replace the defective component.
Check the insulation against earth and continuity between the defective function and the UPC:
Cigar lighters, air conditioning control panel, radio,
multifunction display, rear view mirror controls, front
and rear window riser commands and window riser
locking, door locking switch, instrument panel
command and in-situ control of headlights command.Track 6 of connector PPH2 on the UPC
Heated seat switches, rigid roof switches, petrol or
LPG selector switch, electronic stability program
switch, simultaneous window control, automatic
gearbox display and speed limiter / cruise control
commands.Track 7 connector PPH2 of the UPC
Repair if necessary.
If the fault is still present, contact the Techline.
AFTER REPAIRDeal with any other possible faults.
Switch off the ignition and carry out a road test followed by a test with the diagnostic
tool.
