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62C-17
MR-413-X44-62C000$455_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Function62C
Exchanges between the two air conditioning computers (manual air conditioning)
–air conditioning request
–switch on heated rear screen request (+ electric door mirrors)
–passenger compartment ventilation signal
MANUAL AIR
CONDITIONING
CONTROL PANELUCH
–Heated rear screen warning light lit
–Air conditioning warning light lit
–Air conditioning request 2
UCHINJECTION
COMPUTER
–Air conditioning authorisation
–Engine status signal
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62C-18
MR-413-X44-62C000$455_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Function62C
Vehicle
multiplex
network
Heated rear screen
resistor relay
Summary of components controlled or managed by the MANUAL AIR CONDITIONING control panel:
Ventilation and air conditioning unit
Passenger
compartment
blower
Resistor
unitRecirculation
flapDistribution
flapMixing
flap
Actuator control
User control panel
User request management
(air conditioning button and
heated rear screen button
pressed)Button lighting (air conditioning
button and heated rear screen
button)Passenger compartment
blower operation signal
(running or stopped)
UCH
Transmission of air conditioning
request
Activation of the heated rear
screen request.
Key:
Wire connections =
Multiplex connections =
Mechanical connections =
(control cables)
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62C-34
MR-413-X44-62C000$637_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Conformity check62C
SUMMARY TABLE OF THE VARIOUS AIR CONDITIONING COMPUTER COMMANDS
Fault finding procedures for the commands listed in this summary are explained in the Workshop Repair Manuals
relating to the computer which generates the signal (see Introduction). Name of sub-function Name of computer Command name Fault finding
COLD LOOPInjection (see 13B, Diesel
injection or 17B, Petrol
injection)AC180: Air conditioning
compressor relay
controlIn the event of a fault, refer
to the interpretation of
this command.
AC153 High speed fan
assemblyIn the event of a fault, refer
to the interpretation of
this command.
AC154 Low speed fan
assemblyIn the event of a fault, refer
to the interpretation of
this command.
HEATINGUCH (see 87B,
Passenger
compartment
connection unit)AC060 Rear screen de-
icerIn the event of a fault, refer
to the interpretation of
this command.
Injection (see 13B, Diesel
injection or 17B, Petrol
injection)AC250 Heating resistor
relay 1In the event of a fault, refer
to the interpretation of
this command.
AC251 Heating resistor
relay 2In the event of a fault, refer
to the interpretation of
this command.
USER SELECTIONUCH (see 87B,
Passenger
compartment
connection unit)AC015 Air conditioning
button indicator lightIn the event of a fault, refer
to the interpretation of
this command.
AC019 Heated rear
screen indicator lightIn the event of a fault, refer
to the interpretation of
this command.
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62C-36
MR-413-X44-62C000$728_eng.mif
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MANUAL AIR CONDITIONING
Fault finding - Customer complaints62C
WATER IN PASSENGER COMPARTMENT
WATER IS PRESENT IN PASSENGER COMPARTMENT ALP 12
CONTROL PANEL FAULT
NO CONTROL PANEL LIGHTING ALP 13
COMPRESSOR NOISES
COMPRESSOR NOISES ALP 14
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62C-45
MR-413-X44-62C000$819_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Fault finding charts62C
ALP 5
CONTINUED 3
Disconnect the connector of component 1156, position the speed switch in position V4.
Using a test light, check for + 12 V between connections 38DA and 38DB of component 1156.
Does the test light illuminate?
YES NO
Replace fan assembly 1 (see MR 411 Mechanical,
61A, Heating, Fan assembly control unit:
Removal - Refitting).
Is the continuity correct?
YES NO
Carry out a continuity test on connection 38DB
between components 1156 and 164.
Is the continuity correct?
YES NO
End of procedure. Fault on connection 38DB between components 1156
and 164. Repair the wiring. If there is a repair
procedure (see Technical Note 6015A, Repairing
electrical wiring, Wiring: Precautions for repair),
repair the wiring, otherwise replace it.
Carry out a continuity test on connection 38DA
between components 1156 and 164.
Fault on connection 38DA between components 1156
and 164. Repair the wiring. If there is a repair
procedure (see Technical Note 6015A, Repairing
electrical wiring, Wiring: Precautions for repair),
repair the wiring, otherwise replace it.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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62C-46
MR-413-X44-62C000$819_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Fault finding charts62C
ALP 5
CONTINUED 4
Using a test light, check for + 12 V between connection SP2 and earth MAM.
Is the test light lit?
YES NO
Using a test light, check for + 12 V between
connection BP1 of component 1428 and a chassis
earth.Using a test light, check for + 12 V between
connnection SP2 and a chassis earth.
Is the test light lit? Is the test light lit?
YES NO YES NO
Activate speed 1 and,
using a test light, check for
+ 12 V between
connection SP3 of
component 1156 and a
chassis earth.Carry out a continuity
test on connection
BP1 between
component 1428 and
fuse
F24 (30A) of
component 1016.Fault on connection MAM.
Repair the wiring. If there is a
repair procedure (see Technical
Note 6015A, Repairing
electrical wiring, Wiring:
Precautions for repair), repair
the wiring, otherwise replace it.Carry out a
continuity test
on connection
SP2 between
component
1428 and fuse
F29-15A of
component
1016 Is the test light lit? Is the continuity
correct?
YES NO YES NO
Replace the
fan assembly.Replace the
fan assembly
relay.Fault on connection MAM.
Repair the wiring. If there is
a repair procedure (see
Technical Note 6015A,
Repairing electrical
wiring, Wiring:
Precautions for repair),
repair the wiring, otherwise
replace it.
D
Is the continuity correct?
YES NO
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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62C-48
MR-413-X44-62C000$819_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Fault finding charts62C
Preliminary cold loop efficiency test
ALP 8 No cold air
NOTESConsult this customer complaint after a full check with the diagnostic tool
(fault reading and configuration checks).
Check that the engine speed is greater than 750 rpm and that the exterior
temperature is above 3 ˚C.
Check that the fuses are sound.
Use a multimeter and a 21 W test light.
Use the Wiring Diagram Technical Note, New Twingo.
With engine running, air conditioning in maximum
cold position and maximum ventilation speed. After
10 minutes, is the high pressure pipe at the
compressor outlet hot, and the low pressure pipe at
the evaporator outlet cold and iced up?
NO
Check the cleanliness of the condenser. Touch the
pipes: are they warmer at the inlet than the outlet?
YES
Is the dehydrator reservoir pipe hot at the inlet and
outlet?
YES
Is the expansion valve pipe hot at the inlet and
outlet?
NO
Is the evaporator pipe hot at the inlet and outlet?
NO
1
YES2
NOReplace the condenser (see MR 411
Mechanical, 62A, Air conditioning,
Condenser: Removal - Refitting).
NOReplace the dehydrator reservoir (see MR
411 Mechanical, 62A, Air conditioning,
Dehydrator reservoir: Removal -
Refitting).
YESReplace the expansion valve (see MR 411
Mechanical, 62A, Air conditioning,
Expansion valve: Removal - Refitting).
YESReplace the evaporator (see MR 411
Mechanical, 62A, Air conditioning,
Evaporator: Removal - Refitting).
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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62C-51
MR-413-X44-62C000$819_eng.mif
V1
MANUAL AIR CONDITIONING
Fault finding - Fault finding charts62C
ALP 8
CONTINUED 3
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 13B, Diesel injection or 17B, Petrol injection).
Check that the refrigerant fluid pressure is correct (neither too low nor too high) using the PR037 Refrigerant
fluid pressure parameter (see Conformity check, Cold loop sub-function).
Check that the engine cooling fan assembly is at
speed 1 by viewing the following status on the cold
loop sub-function screen:
–Status ET022 Low-speed fan assembly request
should display ACTIVE.
Note:
These statuses are not displayed by all types of
injection (see Conformity check, Cold loop sub-
function).
Does the engine cooling fan operate at low speed?
YES
NOUsing the diagnostic tool, run
command AC154 Low speed fan
assembly relay.
Does the engine cooling fan operate
at low speed?
NO YES
Connector of component 321 disconnected. Connect a
test light between connection 49L of component 321
and the chassis earth and run command AC154 Low
speed fan assembly relay.
Does the test light illuminate?
YES NO
Measure the resistance of component 321, between
connections 49L and 49B of component 321. If the
resistance measured is infinite, replace the fan assembly
resistor (component 321).
Carry out fault
finding on the
injection system
(sub-function: cold
loop and engine
cooling for low
speed fan assembly
activation).
D
AFTER REPAIRCarry out a complete check with the diagnostic tool.