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).
ACREG X84 1.1
Edition 2
MR-372-J84-62B000$020.mif
62B - 9
CLIMATE CONTROL
Fault finding – Allocation of computer tracks62B
V3 MR-372-J84-62B000$030.mif
Vdiag No.: 44
CLIMATE CONTROL
Fault finding – Allocation of computer tracks
Allocation of climate control computer tracks.
Computer
tracksFunctions Sensor - actuator tracks
Connector A
1CAN L
2not used
3not used
4solar sensor signal track 2 of the solar sensor
5interior temperature sensor signal track 4 of the interior temperature sensor
6computer earth
7CAN H
8not used
9+ 12 V side lightsleft-hand side light fuse in the Protection and Switching
Unit (7.5 A)
10 + 12 V accessories feed passenger compartment fuse (15 A)
11 + 12 V before ignition feed passenger compartment fuse (20 A)
12 0 V sensors (solar, interior temperature)track 1 of the solar sensor and track 5 of the interior
temperature sensor
Connector B
1recirculation motor control track 5 of the recirculation motor
2not used
3not used
4not used
5not used
6not used
7passenger compartment blower module
controltrack 6 of the passenger compartment blower module
6-track connector
812 V supply of the mixing and distribution
motorstrack 2 of the mixing and distribution motors
9not used
10 recirculation motor control track 6 of the recirculation motor
11 distribution motor control track 1 of the distribution motor (coil B2)
12 distribution motor control track 6 of the distribution motor (coil A2)
13 distribution motor control track 3 of the distribution motor (coil B1)
14 distribution motor control track 4 of the distribution motor (coil A1)
15 mixing motor controltrack 1 of the mixing motor for B and C84 and track 3
of the mixing motor for J84 (B2 winding)
16 mixing motor control track 6 of the mixing motor (A2 winding)
17 mixing motor controltrack 3 of the mixing motor for B and C84 and track 1
of the mixing motor for J84 (B1 winding)
18 mixing motor control track 4 of the mixing motor (A1 winding)
ACREG X84 1.1
Edition 2
MR-372-J84-62B000$030.mif
