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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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ALP 8
CONTINUED 1
1
Using the diagnostic tool statuses and parameters
screen (UCH heating sub-function), check that the
temperature signals are consistent (no sensor
deviations resulting in incorrect measurement).
–Use statuses PR002 Exterior temperature and
PR024 Engine coolant temperature.
Are the temperature signals consistent?
YES
Start the engine and switch on the air conditioning by
pressing the AC button (with a request for maximum
cold temperature and the passenger compartment
blower running).
2
Display the following status in the “User selection”
sub-function screen:
ET029 Air conditioning button should be
PRESSED.
Note:
The status indicates if the signal for the AC button
pressed on the control panel is read by the UCH
correctly.
Does status ET029 display PRESSED?
YES
NOCarry out a conformity check:
–For the coolant temperature sensor,
see 13B, Diesel injection, Fault
summary table or 17B Petrol
injection, Fault summary table.
–For the exterior temperature sensor,
see 87B, Passenger compartment
connection unit, Fault summary
table.
Replace any faulty components.
NOContinuity fault on connection 38LP.
Using an ohmmeter, carry out a continuity
test on connection 38LP between
components 319 and 645. If there is a
procedure (see Technical Note 6015A,
Repairing electrical wiring, Wiring:
Precautions for repair), repair the wiring,
otherwise replace the wiring.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 8
CONTINUED 4
Check the continuity of connection 49L between components 321 and 700.
Is the continuity correct?
NO YES
Continuity fault on connection 49L. If there is a repair
procedure (see Technical Note 6015A, Repairing
electrical wiring, Wiring: Precautions for repair),
repair the wiring, otherwise replace it.Check that the low speed fan assembly relay operates
correctly (component 700). Replace it if it is faulty (see
MR 411 Mechanical, 81C, Fuses, Fuses: List and
location of components).
D
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 8
CONTINUED 5
Check the air conditioning compressor belt tension
(see Technical Note 3786A, Engine and
peripherals, 10A, Belt tension setting tool Hz
measurement: tension values).
Is the tension correct?
YES
With the engine stopped, use the diagnostic tool to
run command AC180 Air conditioning
compressor relay (injection command mode
menu).
Does the compressor clutch jam?
YES
E
NOReplace the belt (see MR 411
Mechanical, 11A, Top and front of
engine, Accessories belt:
Removal - Refitting).
NO
YESConnect a test light between connections 38R
and MAS of component 171 and run
command AC180 Air conditioning
compressor relay.
Does the test light illuminate?
NO
Connect a test light between connection 38R
of component 171 and the chassis earth, then
run command AC180 Air conditioning
compressor relay.
Does the test light illuminate?
YES
Earth fault on component 171.
If there is a repair procedure
(see Technical Note 6015A,
Repairing electrical wiring,
Wiring: Precautions for
repair), repair the wiring,
otherwise replace the wiring.
Check the condition of the
diode (component 322).
Replace the diode if it is faulty.
Replace the air conditioning
clutch (component 171) if
possible, otherwise replace
the compressor (see MR 411
Mechanical, 62A, Air
conditioning, Compressor:
Removal - Refitting).
NO
F
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ALP 8
CONTINUED 6
Check the continuity and insulation to earth of connection 38R between components 171 and 584.
Is the connection OK?
YES NO
Apply the fault finding procedure for command AC180
Air conditioning compressor relay (see 13B Diesel
injection or 17B Petrol injection).If there is a repair procedure (see Technical Note
6015A, Repairing electrical wiring, Wiring:
Precautions for repair), repair the wiring, otherwise
replace it.
F
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 9 Too much cold air
NOTESConsult this customer complaint after a full check with the diagnostic tool (fault reading and
configuration checks).
Check that the fuses are sound.
Use a multimeter and a 21 W test light.
Use the Wiring Diagram Technical Note, New Twingo.
With the engine at idle speed and the heating and air conditioning off (AC button not pressed), check that the air conditioning
compressor clutch is not engaged.
Is the air conditioning compressor clutch engaged? NO
YES
With the engine stopped, check that the compressor clutch electric control operates correctly, using the diagnostic tool to run
command AC180 Air conditioning compressor relay (injection command mode menu).
–During the command, connection 38R of component 171 must be supplied with + 12 V.
–After the command, connection 38R of component 171 must no longer be supplied with + 12 V.
Is the connection still supplied with + 12 V after the command?
YES NO
Check the continuity and insulation from + 12 V of
connection 38R between components 171 and 584.Check that the air conditioning compressor clutch is not
jammed (mechanical fault).
Is the connection OK? Is the clutch still engaged?
NO YES YES
If there is a repair procedure (see
Technical Note 6015A, Repairing
electrical wiring, W iring:
Precautions for repair), repair the
wiring, otherwise replace it.With the vehicle ignition of f, check that
the compressor clutch relay is not
“jammed”, by checking the continuity
between connection 38R and
connection AP3 of component 584.
Is the continuity present?
NO
Apply the fault finding procedure for command
AC180 Air conditioning compressor relay
(see 13B Diesel injection or 17B Petrol
injection).
Is the fault still present?
Replace the air conditioning
compressor (see MR 411,
Mechanical, 62A, Air conditioning,
Compressor: Removal - Refitting).
YESReplace the air
conditioning
compressor clutch
relay.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 10 Inefficient rear screen de-icing/demisting
NOTESCarry out this conformity check after a full check using the diagnostic tool (fault
reading, especially UCH and injection faults and configuration checks).
Check that the fuses are sound.
Use a multimeter and a 21 W test light.
Use the Wiring Diagram Technical Note, New Twingo.
Special notes:
Check that the inside of the windows are not greasy as this reduces the efficiency of
the de-icing.
Note:
The de-icing control is only authorised when the engine is running to save
power. The rear screen de-icer is controlled by pressing the rear screen de-icer
button (with time delay and rear-view mirror de-icer if fitted).
Ensure that there are no water leaks in the passenger compartment which would significantly increase the
moisture and reduce the effectiveness of the demisting function (see ALP 12 if the fault is noted).
Is the fault still present?
YES NO
Check that the UCH receives the signal about the
status and operation of the engine. In the Cold Loop
screen, status ET142 Engine operating phase
should display RUNNING.
Is status ET142 RUNNING?
YES
End of fault finding procedure.
NOCarry out fault finding on the UCH
(interpretation of status ET142) and on the
multiplex network.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 10
CONTINUED
Press the de-icing button on the control panel and
check status:
–ET028 Heated rear screen button
Does status ET028 display PRESSED?
YES
Connect a test light between connections 15LP and
MYH of component 200 and, using the diagnostic
tool, run command AC060 Rear screen de-icer
(UCH command mode menu).
Does the test light illuminate?
YES
Connect a test light between connection 15LP and
the chassis earth and use the diagnostic tool to
run command AC060 Rear screen de-icer (UCH
command mode menu).
Does the test light illuminate?
NO
Check the continuity of connection 15LP between
components 200 and 645.
Is the continuity correct?
YES
See 87B, UCH, Interpretation of commands, for command AC060 Rear screen de-icer.
NOContinuity fault on connection 15M.
Using an ohmmeter, carry out a continuity
test on connection 15M between
components 319 and 645. If there is a
procedure (see Technical Note 6015A,
Repairing electrical wiring, Wiring:
Precautions for repair), repair the wiring,
otherwise replace the wiring.
NOCheck the resistance of the rear screen
de-icer lines. The line resistance must not
be zero or infinite. If the resistance is not
correct, replace the rear screen (see MR
412, Bodywork, 54A, W indows, Rear
screen window: Removal - Refitting).
YESContinuity fault on connection MYH of
component 200. If there is a repair method
(see Technical Note 6015A, Repairing
electrical wiring, Wiring: Precautions
for repair), repair the wiring, otherwise
replace the wiring.
NOContinuity fault on connection 15LP
between components 200 and 645. If
there is a repair method (see Technical
Note 6015A, Repairing electrical wiring,
Wiring: Precautions for repair), repair
the wiring, if not replace the wiring.
AFTER REPAIRCarry out a complete check with the diagnostic tool.