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Fault finding – Introduction62B
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Vdiag No.: 44
Faults:
Faults are declared as either present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but have not been diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is used after the
+ after ignition feed has been supplied (without acting on the system components).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the instructions in the Notes section.
If the fault is confirmed when the notes are applied, the fault is present. Deal with the fault.
If the fault is not confirmed, check:
–The electrical lines which correspond to the fault,
–The connectors on these lines (corrosion, bent pins, etc.),
–The resistance of the faulty component,
–The condition of the wiring (insulation melted or cut, chafing, etc.).
Conformity check
The aim of the conformity check is to check statuses and parameters that do not produce a fault display on the
diagnostic tool when they are inconsistent. Therefore, this stage is used to:
–carry out fault finding on faults that do not have a fault display, and which may correspond to a customer complaint,
–check that the system is operating correctly and that there is no risk of a fault recurring after repairs.
This section gives the fault finding procedures for statuses and parameters and the conditions for checking them.
If a status is not behaving normally or a parameter is outside the permitted tolerance values, consult the
corresponding fault finding page.
Notes about the conformity check for the air conditioning system
All variables (statuses and parameters) and commands required for the air conditioning function are divided into four
sub-functions:
–the COLD LOOP sub-function, which groups together all the information required for producing cold air,
–the USER SELECTION sub-function, which groups together all the information relating to the user's requests
(buttons pressed, warning lights, etc.),
–the HEATING sub-function, which groups together all the information required for producing warm air,
–the PASSENGER COMPARTMENT VENTILATION sub-function, which groups together all the information
relating to ventilation, distribution and air distribution within the passenger compartment.
ACREG X84 1.1
Edition 2
62B - 7
CLIMATE CONTROL
Fault finding – System operation62B
V3 MR-372-J84-62B000$020.mif
Vdiag No.: 44
CLIMATE CONTROL
Fault finding – System operation
GENERAL INFORMATION:
The climate control system fitted on the SCENIC is controlled by four computers. This system is called a
DISTRIBUTED FUNCTION. Fault finding on the climate control is performed in two different ways using the
diagnostic tool. The first method consists of performing fault finding on each computer which allows
communications to be established with just one computer (select the climate control computer). The second
procedure consists of performing fault finding on each function which allows communications to be established
with all four computers of the AIR CONDITIONING function. These two fault finding methods are described in the
introduction of this repair manual.
DESCRIPTION OF THE OPERA
TION OF THE CLIMATE CONTROL COMPUTER:
The climate control computer controls the passenger compartment ventilation, the distribution motor, the mixing
motor and the recirculation motor.
The climate control computer also controls two sensors, these being the interior temperature sensor and the solar
radiation sensor.
The two sensors and the three motors are connected to the climate control computer by wire connections. The
climate control computer controls the passenger compartment ventilation using a modulated control signal (square
signal) sent to a power module (wire connection).
All other signals used by the climate control computer or transmitted by this computer to other computers are sent on
the multiplex network.
Cold air production (cold loop) and warm air production (heating) are controlled by the other three computers
involved in the Air conditioning function (UCH, protection and switching unit and injection computer).
The main signals used by the climate control computer are:
–+ 12 V sidelights,
–0 V rheostat controlled,
–exterior temperature,
–engine coolant temperature,
–engine operating status,
–engine speed,
–electrical power consumed,
–request to set the blown air temperature.
OPERA
TING NOTES:
–When the engine is switched off, the passenger compartment blower unit operates approximately 30% slower than
the requested speed (control panel setting).
–If any of the actuators are faulty, the air conditioning can no longer control them, but the setting requests are still
displayed on the control panel: warning lights light up, display of symbols on the control panel (distribution motor
position, passenger compartment blower speed, AC symbol, etc.).
–If the exterior temperature sensor is faulty, the climate control computer is switched on 5 seconds after the
ignition is switched on (this allows a fault to be identified as fault finding cannot be performed on the exterior
temperature sensor by the UCH).
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MR-372-J84-62B000$020.mif
62B - 10
CLIMATE CONTROL
Fault finding – Configurations and programming62B
V3 MR-372-J84-62B000$040.mif
Vdiag No.: 44
CLIMATE CONTROL
Fault finding – Configurations and programming
CLIMATE CONTROL COMPUTER CONFIGURATION:
The climate control computer has 2 configuration functions. These configurations need to be set after the computer
has been replaced.
These two configurations are important as they ensure air conditioning is optimised within the vehicle (better control
of automatic climate control). If they are not correctly entered, cold air and warm air production will be severely
affected (e.g. heating resistors will not be switched on to heat the passenger compartment air).
These configurations can be accessed in repair mode by the diagnostic tool and can only be entered using
the fault finding by computer menu as opposed to the fault finding by function menu.
These configurations can be read, also using the diagnostic tool in repair mode to ensure they have been correctly
set. Configurations can be read in both fault finding by computer mode and fault finding by function mode.
–The first configuration is CF044 Vehicle type; this configuration allows you to enter the body type to which the
climate control computer is fitted (J84/R84 for 4 wheel drive Mégane Scénic and Scénic, and OTHER X84 for all
other Méganes). The configuration reading is called: LC013 Vehicle type.
–The second configuration is CF117 Type of heating resistors; this configuration is used to enter the type of
passenger compartment air heating resistors fitted in the vehicle. There are three options: WITHOUT for vehicles
without 1000 W and 1800 W resistors.
Heating resistors are mainly fitted on vehicles with Diesel engines.
They are located in the ventilation - air distribution unit (left-hand side), next to the heater matrix. The label affixed
to the resistor unit (with the part number) specifies whether the resistors are 1000 or 1800 W (Note: 1800 W
resistors are mainly fitted to Mégane Scénics). This configuration reading is called: LC043 Heating resistor.
Note:
In fault finding by function mode, the diagnostic tool can also display the configuration readings of the other computers
involved in the air conditioning function. All configurations of the air conditioning function (injection computer, UCH
and Protection and Switching Unit) are listed in Section 62A Air conditioning.
MIXING
AND DISTRIBUTION MOTOR PROGRAMMING PROCEDURE (self-setting):
There is no specific programming operation for the mixing motor and the distribution motor.
However, the minimum and maximum limits of these motors have to be programmed. This operation is automatic and
is performed in the following cases:
–after replacing the mixing or distribution motor,
–after disconnecting the battery or after disconnecting the climate control computer supply fuse,
–if a fault, declared as present when the ignition was switched off, disappears the next time the ignition is switched
on.
IMPORTANT
To ensure this programming operation is performed correctly, the passenger compartment blower must be
switched off (speed set to 0).
ACREG X84 1.1
Edition 2
MR-372-J84-62B000$040.mif
62B - 22
CLIMATE CONTROL
Fault finding – Interpretation of statuses62B
V3 MR-372-J84-62B000$070.mif
Vdiag No.: 44
CLIMATE CONTROL
Fault finding – Interpretation of statuses
ET007
COMPUTER + AFTER IGNITION FEED
NOTESNone.
This status shows the + 12 V after ignition feed supplied by the Protection and Switching Unit.
When the ignition is off, the status displays: ABSENT.
When the ignition is on, the status displays: PRESENT.
If the fault is still present, carry out fault finding on the Protection and Switching Unit: Check that status
ET003 After ignition relay control is working correctly and check that fault DF001 After ignition relay control
circuit is not present.
Carry out any repairs necessary (see corresponding fault finding procedures).
If the fault is still present: disconnect connector A (12-track) from the climate control computer to check the
insulation, continuity and absence of interference resistance of the following connections:
Computer connector A track 10 + accessories feed (7.5 A fuse in the Protection and
Switching Unit)
Computer connector A track 11 + before ignition feed (20 A fuse of the UCH)
Computer connector A track 6 Earth (left-hand dashboard beam)
Repair if necessary.
If the connections are correct and the climate control computer is correctly supplied but the fault is still present:
carry out fault finding on the electric charge circuit.
AFTER REPAIRRepeat the conformity check from the start.
ACREG X84 1.1
Edition 2
MR-372-J84-62B000$070.mif
62B - 23
CLIMATE CONTROL
Fault finding – Interpretation of statuses62B
V3 MR-372-J84-62B000$070.mif
Vdiag No.: 44
ET062
RECIRCULATION FLAP POSITION
NOTESSpecial notes:
Climate control does not have automatic recirculation. However, in extreme
temperatures (above 35 ˚C) and when the air conditioning is switched on, the
recirculation flap sets itself to the recirculation position in order to warm up the
passenger compartment more quickly.
This status specifies the position of the recirculation flap.
If the flap is in the external air position, the status displays: OPEN.
If the flap is in the recirculation position, the status displays: CLOSED.
If the status does not operate as shown, use the fault finding procedure for fault DF021 Recirculation motor
circuit.
AFTER REPAIRRepeat the conformity check from the start.
ACREG X84 1.1
Edition 2
62B - 24
CLIMATE CONTROL
Fault finding – Interpretation of statuses62B
V3 MR-372-J84-62B000$070.mif
Vdiag No.: 44
ET085
HEATED REAR SCREEN: AUTO MODE
NOTESNone.
This status specifies whether the heated rear screen is operated in automatic mode or not. This mode
corresponds to the SEE CLEAR function. This function switches on the heated rear screen, the heated door
mirrors, the air conditioning and the windscreen ventilation at high speed.
The heated rear screen will operate for as long as the SEE CLEAR function is requested (permanently
controlled).
This automatic mode is obtained by pressing the de-icing button at the top of the air conditioning control panel.
If the SEE CLEAR function is requested, the status should display: ACTIVE.
If the SEE CLEAR function is not requested, the status should display: INACTIVE.
If the status does not operate as shown, refer to ALP 10 in Section 62A Air conditioning.
AFTER REPAIRRepeat the conformity check from the start.
ACREG X84 1.1
Edition 2
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CLIMATE CONTROL
Fault finding – Interpretation of statuses62B
V3 MR-372-J84-62B000$070.mif
Vdiag No.: 44
ET086
HEATED REAR SCREEN: MANUAL MODE
NOTESNone.
This status specifies whether the heated rear screen is being operated in manual mode. This mode
corresponds to a timed operating period for the heated rear screen, controlled by the UCH.
This timed period depends on the exterior temperature (approximately 15 minutes).
Operation in manual mode is obtained by pressing the de-icing button at the bottom of the air conditioning
control panel. This function is used to switch on the heated rear screen and the heated door mirrors.
If operation of the heated rear screen is requested in manual mode, the status should display: ACTIVE.
If operation of the heated rear screen is not requested, the status should display: INACTIVE.
If the status does not operate as shown, refer to ALP 10 in Section 62A Air conditioning.
AFTER REPAIRRepeat the conformity check from the start.
ACREG X84 1.1
Edition 2
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CLIMATE CONTROL
Fault finding – Interpretation of statuses62B
V3 MR-372-J84-62B000$070.mif
Vdiag No.: 44
ET141
PASSENGER COMPARTMENT BLOWER
NOTESSpecial note:
This status is used by the UCH to authorise engagement of the passenger
compartment heating resistors (RCH): operating safety.
This status shows the operation of the passenger compartment blower.
When the passenger compartment blower is operating (from speed 1 to speed 8), the status displays:
RUNNING.
When the passenger compartment blower is not operating (speed 0), the status displays: STOPPED.
If the status does not operate as displayed, check that the passenger compartment blower is operating
correctly. If the passenger compartment blower does not work, apply the fault finding procedure in ALP 5 no
passenger compartment ventilation.
If the passenger compartment blower works correctly but the status displays the message STOPPED, check
that the passenger compartment blower visual return (propeller symbol) on the control panel works correctly
(increase in propeller bargraphs according to the eight speeds).
If the passenger compartment blower visual return (propeller symbol) does not work: Contact your Techline.
If the fault is still present, carry out fault finding on the multiplex network.
AFTER REPAIRRepeat the conformity check from the start.
ACREG X84 1.1
Edition 2