ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation87G
87G-10V7 MR-372-J84-87G050$110.mif
UPC
Vdiag No.: 48, 4C
Only on vehicles with M9R injection:
The injection computer also acts on the alternator regulation voltage. The injection computer sends the maximum
authorised power delivered by the engine, to the UPC computer via the multiplex network. If the power from the engine
is less than the power consumed by the alternator, the UPC computer will reduce the alternator voltage.
For vehicles with any injection type except M9R:
The UPC sends the alternator charge to the injection to regulate the idling speed.
c) Starter
This turns the engine over to make it start, and requires a very powerful electric current, which the battery must be
able to supply.
The computer receives the starter activation request via the multiplex network from:
–injection,
–UCH,
–the automatic gearbox.
(see ET010 Starting conditions met)
The computer controls the starter relay.
In the event of a fault with the starter, refer to section 16A, Starting - Charging, Starter.
3 - Keyless vehicle
Under the keyless vehicle function, the Protection and Switching Unit is involved in the starting sub-function. The
computer:
–receives the supply request from the passenger compartment starter via the multiplex network, as well as the clutch
pedal position,
–controls the starter relay,
–inhibits or cuts out this relay control according to a signal prohibiting starting which is sent by the injection computer
or gearbox via the multiplex network (see 87B, Passenger compartment connection unit).
4 - Air conditioning
For the operation of the air conditioning and the role of the Protection and Switching Unit in the control of this
function (see 62A, Air conditioning).
Cold loop:
The computer receives the compressor switch-on request from the injection via the multiplex network.
The computer controls the compressor clutch engagement relay.
Heating:
The computer manages the alternator charge and sends back the signal over the multiplex network.
The computer also controls the rear screen de-icing.
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Conformity check87G
87G-59V7 MR-372-J84-87G050$440.mif
UPC
Vdiag No.: 48, 4C
FUNCTION: AIR CONDITIONING
SUB-FUNCTION: COLD LOOP
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine stopped, + after ignition feed on.
FunctionParameter or Status
Check or ActionDisplay and Notes Fault finding
Compressor
controlAC008:Compressor
controlYou should be able to hear
the compressor clutch
(stops the motor running).In the event of a fault, apply the
procedure for dealing with
command AC008.
Fan assemblyAC009:Low-speed fan
assemblyThis command is used to
activate the fan assembly
at low speed.In the event of a fault, apply the
procedure for dealing with
command AC009.
AC010:High-speed fan
assemblyThis command is used to
activate the engine cooling
fan at high speed.In the event of a fault, apply the
procedure for dealing with
command AC010.
Low-speed
engine fan
assembly relay
controlET014:Low-speed
engine fan
assembly relay
controlINACTIVE
ACTIVEIn the event of a fault, consult
the interpretation for status
ET014.
High-speed
engine fan
assembly relay
controlET013:High-speed
engine fan
assembly relay
controlINACTIVE
ACTIVEIn the event of a fault, consult
the interpretation for status
ET013.
