cooling RENAULT SCENIC 2010 J95 / 3.G Air Conditioning Workshop Manual

62A - 7
AIR CONDITIONING
Fault finding - Function architecture62A
V4
Air conditioning system design
The air conditioning system uses four computers. The four computers are connected by the multiplex system, except
in the case of manual air conditioning, where the connection between the air conditioning control panel and the UCH
is by normal wiring.
The air conditioning control panel interprets the driver's wishes and transmits them to the other computers; it also
manages the passenger compartment ventilation, air distribution, air mixing and air recirculation.
The UCH transmits the request to engage the air conditioning compressor to the injection and controls the operation
of the passenger compartment heating resistors (RCH).
The injection receives the refrigerant fluid pressure signal from the pressure sensor. The injection computer
authorises or inhibits the request to engage the compressor depending on how the vehicle is operating and transmits
the signal to the Protection and Switching Unit (UPC).
The role of the UPC is to manage the power section of the air conditioning system. It controls the engagement of the
compressor, the engine cooling fan units and the heated rear screen.
GLOSSARY
RCH = passenger compartment air heating resistors
AC control panelUCH
–interpretation of driver's
wishes
–passenger compartment
ventilation management
–air distribution management
–air mixing management–passenger compartment air
heating resistors operation
management
UPC
(Power and Switching Unit)Injection computer
–engine unit management
–
compressor control
–
heated rear screen control–air conditioning authorisation
Manual air conditioning
and
Climate controlAIR CONDITIONING
Fault finding - Function architecture
CLIM X84 1.1
Edition 2
MR-372-J84-62A000$030.mif

62A - 9
AIR CONDITIONING
Fault finding - Mode of operation62A
V4MR-372-J84-62A000$010.mif
Exchanges between the four air conditioning system computers
–air conditioning request 1 (compressor
engagement)
–switch on passenger compartment heating
resistors (RCH) request
–switch on heated rear screen request
(+ electric door mirrors)
–passenger compartment ventilation signal
Climate
control panelUCH
–passenger compartment heating resistors (RCH)
operation management
–exterior temperature signal
–engine coolant temperature signal
–switch on heated rear screen request
(+ electric door mirrors)
UCHUPC
(Power and Switching Unit)
–alternator charge signal
–number of passenger compartment heating
resistors authorised by alternator
–air conditioning request 2 (compressor
engagement)
–fast idle request for passenger compartment
heating resistors (RCH)
UCHInjection computer
–compressor engagement authorisation
–engine coolant temperature signal
–refrigerant fluid pressure signal
–number of passenger compartment heating
resistors authorised by injection
–compressor engagement request
–switch on engine cooling fan request
Injection computerUPC
(Power and Switching Unit)
–alternator charge signal
Manual air conditioning
and
Climate control
CLIM X84 1.1
Edition 2
MR-372-J84-62A000$040.mif

62A - 13
AIR CONDITIONING
Fault finding - Mode of operation62A
V4MR-372-J84-62A000$010.mif
Summary of components controlled or managed by the UCH
Summary of components controlled or managed by the Protection and Switching Unit
Passenger
compartment
heating
resistors (RCH)
relay No. 2 Passenger
compartment
heating
resistors (RCH)
relay No. 1 Passenger compartment
heating resistors (RCH)
relay No. 3 (Scénic only)Exterior
temperature
sensor
Vehicle
multiplex
network
Actuator control Sensor management
UCH
Air conditioning request
managementHeated rear screen
control
managementPassenger compart-
ment heating resistor
control management
Engine cooling
fan unitHeated rear
screen and
heated door
mirrorsClimate control
compressorAlternator:
"DF"
terminal
Actuator control Electrical availability management
UPC
"DF" terminal signal formatting
(alternator charge)
Key:
Wire connections =
Multiplex connections =
Manual air conditioning
and
Climate control
CLIM X84 1.1
Edition 2
MR-372-J84-62A000$040.mif

62A - 14
AIR CONDITIONING
Fault finding - Mode of operation62A
V4MR-372-J84-62A000$010.mif
Manual air conditioning
and
Climate control
Summary of components controlled or managed by the injection computer
Refrigerant fluid
pressure sensorEngine coolant
temperature
sensorVehicle
multiplex
network
Sensor management
Engine injection computer
Management of the cold loop (refrigerant fluid pressure,
switch on engine cooling fan request, compressor
engagement authorisation, etc.)Passenger compartment
heating resistors (RCH)
authorised power
management
Key:
Wire connections =
Multiplex connections =
CLIM X84 1.1
Edition 2
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62A - 21
AIR CONDITIONING
Fault finding - Conformity check62A
V4
Manual air conditioning
and
Climate control
Subsystem: cold loop (continued 4)
Computer
(signal generator)Parameter or status
checked or actionDisplay and Notes Fault finding
Protection and
Switching UnitET007:High speed fan
control.INACTIVE
(On Mégane saloons and
sport hatches this status is
always
ACTIVE: ignore it
).If there is a fault, refer to the
fault finding procedure
for this status.
NOTE: This status is only
operative on Mégane
Scénics (2 engine cooling
fans and Fan unit 2 relay
outside the UPC).
AC008:Compressor
control.Command for testing the
operation of the air
conditioning compressor
clutch.If there is a fault, consult the
fault finding procedure
for this command.
NOTE: The UPC cannot
test the compressor control
circuit; this command is the
only way to test its
operation.
AC009:Low speed fan
unit.Command for testing the
low speed operation of the
engine cooling fan unit
(Fan unit 1).If there is a fault, consult the
fault finding procedure
for this command.
NOTE: The UPC cannot
test the control circuit for
Fan unit 1; this command is
the only way to test its
operation.
AC010:High speed fan
unitCommand for testing the
high speed operation of
the engine cooling fan unit
(Fan unit 2).If there is a fault, consult the
fault finding procedure
for this command.
NOTE: On Mégane saloons
and sport hatches the UPC
cannot test the control
circuit for Fan unit 2; this
command is the only way to
test its operation.
On Mégane Scénics, the
Fan unit 2 control relay is
outside the UPC and its
control line is tested by
(DF002 High speed fan
control relay circuit).
CLIM X84 1.1
Edition 2
MR-372-J84-62A000$060.mif

62A - 34
AIR CONDITIONING
Fault finding - Conformity check62A
V4
Manual air conditioning
and
Climate control
Subsystem: cold loop (continued 4)
Computer
(signal generator)Parameter or status
checked or actionDisplay and Notes Fault finding
Protection and
Switching UnitET007:High speed fan
control.INACTIVE
(On Mégane saloons and
sport hatches this status is
always ACTIVE: ignore it
).If there is a fault, refer to the
fault finding procedure
for this status.
NOTE: This status is only
operative on Mégane
Scénics (2 engine cooling
fans and Fan unit 2 relay
outside the UPC).
AC008:Compressor
control.Command for testing the
operation of the air
conditioning compressor
clutch.If there is a fault, consult the
fault finding procedure
for this command.
NOTE: The UPC cannot
test the compressor control
circuit, this command is the
only way to test its
operation.
AC009:Low speed fan
unit.Command for testing the
low speed operation of the
engine cooling fan unit
(Fan 1).If there is a fault, consult the
fault finding procedure
for this command.
NOTE: The UPC cannot
test the control circuit for
Fan unit 1; this command is
the only way to test its
operation.
AC010:High speed fan
unitCommand for testing the
high speed operation of
the engine cooling fan unit
(Fan 2).If there is a fault, consult the
fault finding procedure
for this command.
NOTE: On Mégane saloons
and sport hatches the UPC
cannot test the control
circuit for Fan unit 2; this
command is the only way to
test its operation.
On Mégane Scénics, the
Fan unit 2 control relay is
outside the UPC and its
control line is tested by
(DF002 High speed fan
control relay circuit).
CLIM X84 1.1
Edition 2
MR-372-J84-62A000$060.mif

AIR CONDITIONING
Fault finding - Fault Finding Chart62A
62A-51V4 MR-372-J84-62A000$080.mif
Manual air conditioning
and
Climate control
ALP 8
CONTINUED 2
Carry out fault finding on the injection system to ensure that no fault is present (if faults are displayed by the
injection computer, engagement of the air conditioning may be inhibited).
If there are present or stored faults: carry out the necessary repairs (see the injection Technical Note).
Check that the refrigerant fluid pressure is correct (neither too low nor too high) using parameter PR037
REFRIGERANT FLUID PRESSURE: see the conformity check in this note (cold loop sub-function).
Check that the engine cooling fan assembly is at speed 1
by viewing the following statuses on the cold loop sub-
function screen:
–Status ET014 FAN ASSEMBLY 1 CHECK should display
RUNNING.
–status ET022 LOW SPEED FAN ASSEMBLY REQUEST
should display ACTIVE.
NOTE: These statuses are not displayed by all types of
injection system (see the cold loop sub-function conformity
check).
Is the engine fan running at speed 1?
YES
NOCarry out fault finding on the
injection (which calls for the fan
units to be switched on) and the
Switching Protection Unit (which
controls the fan units).
AFTER REPAIRPerform a complete check using the diagnostic tool.
CLIM X84 1.1
Edition 2

62A-59
AIR CONDITIONING
Fault finding - Fault Finding Chart62A
V4 MR-372-J84-62A000$080.mif
Manual air conditioning
and
Climate control
ALP 14 Air conditioning noises during operation
NOTESOnly deal with this customer complaint after a full check with the diagnostic tool
(fault reading and configuration checks).
Check that the computers involved in the air conditioning function (Injection, Protection and
Switching Unit, UCH and Air conditioning control panel) are correctly configured.
Reconfigure if necessary (see Configurations and Configuration readings).
Check that:
–the compressor fitted to the vehicle corresponds correctly to the engine (see MR 370 Mechanical, 62A, Air
conditioning, Air conditioning: Parts and consumables for the repair).
Replace the compressor if necessary (see MR 370, Mechanical, 62A, Air conditioning, Compressor: Removal
- Refitting).
–the compressor is correctly fixed (see MR 370 Mechanical, 62A, Air conditioning, Compressor: Removal -
Refitting).
Check the condition of the compressor belt and check its tension. Replace the belt if necessary (see MR 370
Mechanical, 11A, Top and front of engine, Accessories belt: Removal - Refitting).
Check that the intermediate pipes, condenser and dehydrator reservoir are correctly fitted.
–Check the mountings and brackets of the components.
–Check the contact between and proximity of the components.
(see MR 370 Mechanical, 62A, Air conditioning, Air conditioning: List and location of components).
Check the correct operation of the cooling fan assembly or passenger compartment fan assembly and
condenser:
–check the electrical supply of the fan using parameters ET007 High speed fan assembly control, AC009 Low
speed fan assembly and AC010 High speed fan assembly (see Conformity check, Sub-function: Cold
loop).
Check the quantity of refrigerant (see MR 370 Mechanical, 62A, Air conditioning, Air conditioning: Parts and
consumables for the repair).
If the quantity of refrigerant is:
- Greater than the manufacturer's information, recharge according to the manufacturer's values (see MR 370
Mechanical, 62A, Air conditioning: Draining - Filling).
- Less than the manufacturer's information, check for leaks (see MR 370 Mechanical, 62A, Air conditioning,
Refrigerant circuit: Check).
If the fault is still present, replace the compressor (see MR 370, Mechanical, 62A, Air conditioning,
Compressor: Removal - Refitting).
AFTER REPAIRPerform a complete check using the diagnostic tool.
CLIM X84 1.1
Edition 2